The Doctor

"The Doctor", a title embodying their promise to the universe, was the main alias used by a mysterious traveller of both space and time, seemingly a renegade Time Lord from Gallifrey. The Doctor adventured with numerous companions in an obsolete and "borrowed" Type 40 TARDIS. They were "the universe's greatest defender", having saved the cosmos thousands of times across a long life, becoming a legend throughout the universe, and a complicated space-time event of unparalleled complexity.

Though largely a believer in non-violent conflict resolution, they were, when absolutely necessary, a great warrior. Indeed, some civilisations in the universe (e.g. the denizens of the Gamma Forests) translated the word doctor as warrior, (TV: A Good Man Goes to War) whilst others saw the Doctor as a compassionate benefactor, worthy of their admiration and compassion. (TV: Last of the Time Lords, The Wedding of River Song)

Although they had saved untold numbers on their travels, as the Champion of Life, (PROSE: Vampire Science, TV: The Vanquishers) even in darkness, (AUDIO: Light the Flame, TV: Extremis) the Doctor was thought to have caused the deaths of billions at the end of the Last Great Time War, (TV: Dalek) as well as countless others before and after, when available options were limited and others were caught in the crossfire. (TV: Thin Ice, Extremis)

Though most of the Daleks were destroyed on the final day of the Time War, most accounts of those final moments held that Gallifrey was hidden, rather than being burned, through the combined efforts of at least thirteen, possibly all of, the Doctor's incarnations, the first eleven of whom retained no memory of the event. (TV: The Day of the Doctor, PROSE: The Day of the Doctor, PROSE: Dalek Combat Training Manual) For their actions, the Time Lords granted the Doctor a new regeneration cycle, allowing them to live on after using up all twelve available regenerations in their first cycle. (TV: The Time of the Doctor)

The Doctor's personal history was constantly changing and contradicting itself. (PROSE: Unnatural History) Their early life and their true species were matters of much contention, in part due to shifting timelines. (PROSE: Celestial Intervention - A Gallifreyan Noir) The Doctor's own memories were unclear regarding their early life and origins, (COMIC: The World Shapers; PROSE: Who is Dr Who?, Unnatural History) and several accounts even suggested that they had non-Gallifreyan origins, either human (TV: The Evil of the Daleks; PROSE: Doctor Who and the Daleks, The Monsters from Earth) or of an unknown species. (TV: The Timeless Children)

According to one account, the Doctor was some form of reincarnation of the Other, a mysterious figure from Gallifrey's past who helped form Time Lord society and perfect time travel technology. The Other would later become the Doctor by looming himself. (PROSE: Lungbarrow) Indeed, the Doctor explicitly told Davros that they were "far more than just another Time Lord", (TV: Remembrance of the Daleks) and Lady Peinforte claimed knowledge of the Doctor's actions during the Dark Times of early Gallifrey. (TV: Silver Nemesis)

According to another account, the Doctor was originally "the Timeless Child", a being from an unknown realm, which possibly lay within another universe. The Child was discovered by the First Tecteun early in Gallifreyan history, and had a natural ability to regenerate, which Tecteun studied and eventually replicated. Eventually the Shobogans, Tecteun's people, became Time Lords, and the origin of regeneration was covered up by the Founding Fathers of Gallifrey in favour of a "noble creation myth" instead. (TV: The Timeless Children) Indeed, it was Tecteun themself who ordered that the Doctor's memories be redacted after their service to the Division was complete, which resulted in the Doctor being unaware of their true nature, (TV: Survivors of the Flux) and in Time Lord civilisation being built on a lie. (TV: Spyfall)

From the latter years of their first incarnation onward, the Doctor had a pronounced affinity for Earth and the human race. (TV: The Ark in Space, New Earth, Utopia) After departing Gallifrey, they voluntarily chose to spend time on Earth, (TV: An Unearthly Child; AUDIO: Summer, The Haunting of Thomas Brewster) choosing it as the place of their exile for most of their third incarnation, (TV: The War Games, Spearhead from Space) and even owning property in Kent, (COMIC: Fellow Travellers; PROSE: Warlock, Warchild, The Dying Days) as well as London (AUDIO: The Haunting of Malkin Place, The White Room, Lost Property) and New York City. (PROSE: The Forgotten Army) The Doctor favoured Great Britain in particular, frequently returning, and finding many of their companions there. (TV: An Unearthly Child, Spearhead from Space, The Time Monster, Rose, Smith and Jones, Partners in Crime, et al.) Later on, the Doctor thought of themselves as Earth's protector. (TV: The Eleventh Hour, Twice Upon a Time, Resolution) Even before the disappearance of Gallifrey, the Doctor spent much more time on Earth than on their homeworld, as "home from home". (PROSE: The Rag & Bone Man's Story; AUDIO: A Thing of Guile)

Despite the varying personality traits of each incarnation, the Doctor always retained "a bit of adrenaline, a dash of outrage and a hint of panic", which helped define who they were, (TV: The Woman Who Fell to Earth) and a questionable fashion sense according to many, (TV: The Power of Three) along with the promise of sticking to everything that their name stood for: duty, compassion, and resourcefulness. (TV: The Day of the Doctor)

Trouble seemed to follow the Doctor, (TV: Inferno) by their own admission. (TV: Marco Polo) They spent much of their time bounding from one place to another, with "all of time and space" to explore, (TV: The Eleventh Hour) solving problems with whatever was at hand, (TV: Time Crash) making friends (AUDIO: Companion Piece) and enemies, (TV: The Pandorica Opens) and rarely looking back, (TV: Journey's End) always having an eye on their next destination. (TV: Utopia)

Name
The Doctor's true name remained unknown to all but a very few individuals, such as Sam Jones, (PROSE: Vanderdeken's Children) River Song, (TV: Forest of the Dead, The Name of the Doctor) and the Master. (TV: World Enough and Time) Though the Time Lords knew the genuine name of the Doctor, (TV: The Time of the Doctor) they did not use it in the formal setting of the majority of their legal trials. (TV: The War Games, The Trial of a Time Lord)

According to, he chose the name "Doctor" to reflect his constant desire to make people "better". (TV: The Sound of Drums) claimed to know the Doctor's real name from their time together on Gallifrey; she said it was "Doctor Who", and the Doctor had chosen it to be mysterious but dropped the "Who" when he realised it was too on-the-nose. (TV: World Enough and Time) Indeed, several accounts suggested that "Doctor Who" was a proper way to address the time traveller. (TV: The War Machines; PROSE: Doctor Who and the Space War, et. al)

The Eleventh Doctor told Clara Oswald that his real name was not so important, since he specifically chose in its place the title of "Doctor", "like a promise you make". (TV: The Name of the Doctor) This promise was, as the Tenth and War Doctor recited together, "Never cruel or cowardly. Never give up, never give in." (TV: The Day of the Doctor) The Twelfth Doctor claimed that when he originally adopted the title it was "just a name," which held no real significance until his first visit to Skaro. It was through his opposition to the Daleks that the Doctor was able to define himself and realise who he was. (TV: Into the Dalek)

The title "Doctor" was not undeserved; they did hold one or more doctorates of some sort, (TV: The Armageddon Factor, The God Complex) formally studied medicine on at least 19th century Earth at Glasgow University, (TV: The Moonbase) and frequently displayed detailed medical knowledge. (TV: The Ark, Frontios, The Empty Child, New Earth, The Time of Angels, The Curse of the Black Spot) At least some versions of their sonic screwdriver performed medical scans and healed minor wounds. (TV: The Empty Child, The Vampires of Venice, A Good Man Goes to War) The Seventh Doctor showed knowledge on how to help someone thrown by an explosion recover quickly. (TV: Remembrance of the Daleks) Although their first, (TV: "The Forest of Fear", "Mighty Kublai Khan") second, (TV: The Krotons) fourth (TV: The Ark in Space) and fifth incarnations (AUDIO: Red Dawn) had claimed not to be a doctor of medicine, their third, (TV: Spearhead from Space) eighth, (AUDIO: Sword of Orion) ninth (COMIC: The Cruel Sea) and tenth incarnations (TV: Utopia) claimed to be a doctor of practically "everything", and by their eleventh incarnation, the Doctor claimed to hold doctorates in at least medicine and cheesemaking. (TV: The God Complex) In their thirteenth incarnation, they claimed to be a doctor of "Medicine, science, engineering, candyfloss, Lego, philosophy, people, [and] hope. Mostly hope." (TV: The Tsuranga Conundrum)

According to Evelina, the Doctor's name was written in the stars of the Medusa Cascade. (TV: The Fires of Pompeii) Members of an unidentified race of pan-dimensional beings also knew the Time Lord's real name, at one point. (AUDIO: The Last Voyage)

In one account, he had taken the moniker after his first contact with humans. Colonists on the medical/penal colony of Iwa began calling him "Doctor" after his arrival. He failed to correct them. After they left the planet, "the Doctor" simply kept the name he had been given by the humans. (PROSE: Frayed) In another, he had already been introducing himself by that name after his first trip in the TARDIS, which gave an alternative account of meeting humans for the first time on the Moon. (AUDIO: The Beginning) The First Doctor responded to the name when an echo of Clara Oswald put it to him before even departing Gallifrey. (TV: The Name of the Doctor)

River Song believed that the Doctor had influenced the etymology of the word doctor itself; and in multiple cultures was the first recorded use of "Doctor" (TV: A Good Man Goes to War)

According to Dorium Maldovar and the Silence, the oldest and most dangerous question in the universe was "Doctor who?" The Doctor's true name was apparently the answer. Dorium claimed the Doctor had been running from the question all his life. According to the Silence, "silence must fall when the question is asked," (TV: The Wedding of River Song) because if the question was answered, it could lead to destruction on a universal scale; through several methods, each of which were located on the planet Trenzalore. The first was that the Doctor's name could be used to open his grave and alter his timeline, potentially undoing the countless times the Doctor had saved the universe. (TV: The Name of the Doctor) The second was that his name could be used to confirm to the Time Lords, who were sealed in a pocket universe and had been broadcasting the question throughout the entirety of time and space, that it was safe for them to return; which could result in another Time War. (TV: The Time of the Doctor)

At some point River Song learned his name, prompting the Doctor to claim that there was only one reason he ever would or could reveal it. (TV: Forest of the Dead) Indeed, even while spending hundreds of years in a town permeated by a Truth Field and hearing the question asked multiple times, the Doctor would not or could not answer. (TV: The Time of the Doctor) However, River later stated that she "made him" tell her his true name and that it "took a while". (TV: The Name of the Doctor)

Clara Oswald viewed the Doctor's name in a book on the Time War, contained in the TARDIS library. She subsequently lost the information when time was rewound. (TV: Journey to the Centre of the TARDIS)

Theta Sigma was, by some accounts, the Doctor's true name, (TV: The Armageddon Factor, PROSE: K9 and the Beasts of Vega, et al.) however the Seventh Doctor later claimed that this was merely a nickname he was given at college. (TV: The Happiness Patrol)

Moments before regenerating into the Thirteenth Doctor, the Twelfth Doctor used his last words to leave his future self some advice. Amongst these last words was that the future Doctor must not tell anyone their name, but that they couldn't understand it even if the Doctor did tell them. The Doctor went on to state that "children can hear it, sometimes. If their hearts are in the right place and the stars are too. Children can hear your name. But nobody else, nobody else ever." (TV: Twice Upon a Time)

The Thirteenth Doctor later learned from that in early Gallifreyan history, she had been known as the Timeless Child, the being from whom the Time Lords' ability to regenerate originated. (TV: The Timeless Children)

Age
The Doctor's age was a matter of great confusion, as they provided many inconsistent statements. The Second Doctor once gave his age in Earth terms as 450. (TV: The Tomb of the Cybermen) On two separate occasions, the Third Doctor implied that he may have been several thousand years old. (TV: Doctor Who and the Silurians, The Mind of Evil) The Fourth Doctor, however, gave his age as "something like 750 years". (TV: Pyramids of Mars) Immediately after his sixth regeneration, the Seventh Doctor claimed to be 953. (TV: Time and the Rani) The War Doctor considered himself 400 years younger than the Eleventh Doctor, who was purportedly 1,200 at that time. (TV: The Day of the Doctor) The Ninth Doctor claimed to be 900 years old. (TV: Aliens of London) The Tenth Doctor claimed to be 903. (TV: Voyage of the Damned) Also, at least prior to leaving Amy and Rory behind, (TV: The God Complex) the Eleventh Doctor maintained an age of 909, less than his seventh incarnation. (TV: Flesh and Stone, The Impossible Astronaut)

The Eleventh Doctor later claimed to the Ponds that he was 1,200 years old (TV: A Town Called Mercy) but clarified to Clara Oswald that he'd lived so long he'd forgotten whether or not he was lying about his age. (TV: The Day of the Doctor) The Twelfth Doctor, after spending 900 years defending Trenzalore, stated his age to be over 2,000. (TV: Deep Breath)

The Twelfth Doctor spent approximately four and a half billion years (TV: Hell Bent) trapped inside his confession dial in an energy loop. In each loop, the Doctor would die, providing energy to a teleporter which would "print" another copy of himself as he was when he first arrived. Although this kept his body from ageing, he claimed to remember the living through every single version of the loop. (TV: Heaven Sent) He later stated to that he was, in fact, four billion years old. (COMIC: Doorway to Hell)

Romana I once caught the Fourth Doctor "rounding down" his age, (TV: The Ribos Operation) while the Eighth Doctor once flatly admitted that he didn't necessarily use the same definition of the word year each time he gave his age to someone, usually changing his age depending where he was in the universe. (AUDIO: Orbis)

The Eleventh Doctor once told Solomon that he was probably a Sagittarius. (TV: Dinosaurs on a Spaceship)

The Thirteenth Doctor once told her companions that she was thousands of years old and was so old she didn't even remember her true age anymore. (TV: Fugitive of the Judoon) She later discovered that she had once been the Timeless Child, a being with infinite regenerative capabilities that led to the Time Lords developing the ability themselves early in their history. The Doctor had her memories of this time redacted however, meaning she was far older than she thought. (TV: The Timeless Children) Rassilon had previously stated that the Time Lords "held a billion years of Time Lord history on [their] backs". (TV: The End of Time) Since the Timeless Child dated back to the beginning of the Time Lords, this would make the Doctor, counting their many forgotten lives as the Timeless Child, at least a billion years old. (TV: The Timeless Children)

Familial relations
The Doctor's familial relations were unclear at best. According to one account, the Doctor was one of the forty-five cousins created by the Loom of the House of Lungbarrow on Gallifrey. (PROSE: Lungbarrow, Celestial Intervention - A Gallifreyan Noir) At other times, the Doctor stated that he had parents, including a Time Lord father (TV: Doctor Who, PROSE: The Infinity Doctors, Unnatural History, Matrix) and a human mother. (TV: Doctor Who, PROSE: Alien Bodies, The Infinity Doctors, Grimm Reality, Unnatural History, The Shadows of Avalon, Celestial Intervention - A Gallifreyan Noir)

However, Lady Peinforte, after reading through TARDIS Wiki, claimed that the Doctor being half human on their mother's side was "much disregarded", (PROSE: Lady Peinforte) and there were many accounts that insisted that the Doctor's mother was also a Time Lord. (COMIC: The Comfort of the Good, et. al) "The Uncle" was the Doctor's uncle. (GAME: The Eternity Clock) The Thirteenth Doctor recalled once having had sisters, (TV: Arachnids in the UK) though another account indicated the Doctor at least never had an older sister. (PROSE: Dragonfire)

The Doctor had at least one brother, Irving Braxiatel, (PROSE: Tears of the Oracle, AUDIO: Disassembled, TV: Smith and Jones) who became an associate of the Doctor's companion Bernice Summerfield. (PROSE: Tears of the Oracle) Braxiatel was also a Cardinal of Gallifrey (AUDIO: Weapon of Choice) and was the owner of the Braxiatel Collection, (PROSE: Tears of the Oracle) which the Doctor and Romana once compared to the Louvre in Paris. (TV: City of Death) The Doctor had one niece by Irving Braxiatel, Maggie Matsumoto. (AUDIO: The Empire State)

At the Doctor's wedding to Scarlette in the post-War universe, the Man with the Rosette sat at the table reserved for the Doctor's family. (PROSE: The Adventuress of Henrietta Street)

The Tenth Doctor told Sally Sparrow that he was "rubbish at weddings, especially [his] own". (TV: Blink) In an alternate universe, an earlier incarnation had been wed (PROSE: Cold Fusion) to Patience and they were said to have had fifteen children and a granddaughter, Susan. (PROSE: The Infinity Doctors)

The Doctor had, in the Tenth Doctor's own words, been "a dad" (TV: Fear Her) and "a father". (TV: The Doctor's Daughter) These children were "sons or daughters, or both." (PROSE: The Eleventh Tiger) The Twelfth Doctor claimed he had "dad skills". (TV: Listen) Clara Oswald also claimed the Doctor had "children". (TV: Death in Heaven)

The Doctor also had several grandchildren, (TV: Death in Heaven) including Susan Foreman (TV: An Unearthly Child, et al.) and John and Gillian Who. (COMIC: The Klepton Parasites, PROSE: Beware the Trods!, et al.) Some accounts referred to Susan as "the Other's" granddaughter. (PROSE: Lungbarrow)

At one point, the Doctor became the adoptive father to a female Time Lord named Miranda Dawkins, whom the Eighth Doctor reared until her mid-teens. (PROSE: Father Time) Miranda later gave birth to a daughter, Zezanne, and died while trying to protect the Doctor. (PROSE: Sometime Never...)

The Doctor also had a great-grandson named Alex, the son of Susan and David Campbell. (AUDIO: An Earthly Child) Alex went on several adventures with the Eighth Doctor and backpacked around the Earth with Lucie Miller before they were both killed by the Daleks. (AUDIO: Lucie Miller, To the Death) Susan and David also had adopted children, Barbara, Ian and David Junior. (PROSE: Legacy of the Daleks)

Much of the Doctor's family died or went missing. (TV: The Tomb of the Cybermen, The Curse of Fenric, AUDIO: To the Death, TV: The Woman Who Fell to Earth) After the last day of the Time War, the Tenth Doctor, while telling Donna that he'd been a father before, explained that he "lost all that a long time ago along with everything else." (TV: The Doctor's Daughter) The Eleventh Doctor involuntarily reacted to Corc's accusation that he had never lost a child. (PROSE: Dark Horizons) Even after the Doctor realised that Gallifrey and the Time Lords were not destroyed at the end of the Time War, the Doctor still believed their missing children and grandchildren to be dead. (TV: Death in Heaven, The Woman Who Fell to Earth)

Genetic material from the Doctor in their tenth incarnation was used to create a daughter, Jenny, via progenation. The Doctor explained to Donna Noble and Martha Jones that due to the way his DNA was processed, he was Jenny's "biological mother and father". Although initially spurning her, he soon considered Jenny his daughter and invited her to travel with him in the TARDIS. Before she could join him, however, she was shot by General Cobb. The Doctor believed Jenny to have died, and departed. (TV: The Doctor's Daughter) Unbeknownst to him, she survived and set out on her own life of adventure. (TV: The Doctor's Daughter, AUDIO: Stolen Goods, et al.)

When the Earth was relocated to the Medusa Cascade, an instantaneous biological meta-crisis was created from the Doctor’s aborted eleventh regeneration ; this meta-crisis Doctor was later was exiled by the Time Lord to an alternate universe. Technically, the meta-crisis could be considered a relative of the Doctor's. Sarah Jane Smith referred to the Doctor's companions as his family, saying, "You act like such a lonely man, but you've got the biggest family on Earth!" (TV: Journey's End)

Affairs
The First Doctor was accidentally engaged to Cameca in the 15th century. (TV: The Aztecs)

After Gallifrey was destroyed in the War in Heaven, the Eighth Doctor married Scarlette in order to ceremonially tie himself to the planet Earth. (PROSE: The Adventuress of Henrietta Street)

The Tenth Doctor romanced and later married Elizabeth I. (TV: The End of Time, The Day of the Doctor, PROSE: Suspicious Minds) She later declared him an enemy after he failed to return as promised. (TV: The Shakespeare Code) The Tenth Doctor implied he had been married several times prior to Queen Elizabeth, as he remarked to Sally Sparrow about being "rubbish at weddings, especially [his] own". (TV: Blink) In his eleventh incarnation, the Doctor accidentally became engaged to Marilyn Monroe, and married her the same night in what he later claimed was not a real chapel. (TV: A Christmas Carol)

River Song often hinted that she and the Doctor had a physical relationship somewhere in her past and his future relative to the Eleventh Doctor's encounter with the Silence in Florida. (TV: Silence in the Library / Forest of the Dead, The Time of Angels / Flesh and Stone, The Pandorica Opens / The Big Bang, Day of the Moon) The Eleventh Doctor, operating a Teselecta shaped like himself, performed a "quick version" of a wedding ceremony with River because they were in the middle of a combat zone in an alternate reality. They repeatedly referred to each other as husband and wife after the ceremony. (WC: Asylum of the Daleks Prequel, TV: The Wedding of River Song, The Angels Take Manhattan, The Name of the Doctor, The Time of the Doctor, The Husbands of River Song, AUDIO: The Boundless Sea, Five Twenty-Nine, The Eye of the Storm, PROSE: Suspicious Minds)

According to Clara Oswald, by the time of the Doctor's twelfth incarnation, he had been "married four times, all deceased". (TV: Death in Heaven)

Throughout the universe
Along their travels, the Doctor's role in events, both great and small, left a lasting impression, being remembered as "the stuff of legend" on Earth (TV: The Christmas Invasion) and beyond. (TV: The Pandorica Opens, AUDIO: Return to Skaro, PROSE: Venusian Lullaby) They had a profound influence on many worlds and was written into their histories, (TV: Forest of the Dead, The Tsuranga Conundrum) passed down, most often, with three big questions: how they vanished, who they were, and why they came to help at all. (TV: World Enough and Time)

As a result, the Doctor was the recipient of many honours, being made a noble of Draconia, (TV: Frontier in Space) a knight and enemy of the British Empire, (TV: Tooth and Claw) and even President of Earth under the incursion protocols. (TV: Death in Heaven, The Pyramid at the End of the World) The Twelfth Doctor recalled that, in one of his lives, he once pulled Excalibur from the stone, becoming "King of England for a day" before abdicating in order to hand the throne over to King Arthur. (PROSE: Silhouette)

Many stories were developed and passed down along the Doctor's adventures. River Song was convinced every story with a "good wizard" ended up being about the Doctor. (TV: The Pandorica Opens) In fact, the Doctor was so accustomed to being made a figure in local mythology that the Thirteenth Doctor felt sidelined when it was her companion instead, Graham O'Brien, being worshipped on a return trip to Lobos. (PROSE: The Good Doctor)

During their time together, the Tenth Doctor and Donna Noble were honoured as household gods by Lobus Caecilius and Metella in Rome, (TV: The Fires of Pompeii) and the Ood's Song of Freedom was dedicated to them, (TV: Planet of the Ood) with their stories being told and re-told all across the worlds they had saved together. (TV: Journey's End)

Tecteun regarded the Doctor as a beacon of hope for the universe, changing worlds and inspiring rebellion wherever they travelled. Since the Doctor could not help but interfere whenever things went wrong, they frequently stood in the way of the Division's plans without knowing, becoming a power they could not account for. As a result of the Doctor's influence, Tecteun sought to end this universe, to begin again without the Doctor. (TV: Survivors of the Flux)

The Doctor's influence on the universe became clear when the Eleventh Doctor's time came to need its help. The Doctor's apparent death at Lake Silencio was a fixed point in time, but River Song prolonged his final moment by refusing to take part, creating River Song's World. As time fell apart, River was desperate to save the Doctor, and built a timey-wimey distress beacon, informing all of time and space that the Doctor was dying. Responses came from all over the universe that they would help. According to her, the Doctor's impact on the universe was so profound that if he ever needed help, all he had to do was ask. (TV: The Wedding of River Song)

Perhaps the Doctor's greatest influence was on their companions, who were inspired by the Time Lord to fight injustice and help those in need. (TV: Death of the Doctor, Revolution of the Daleks) Even those who had never met the Doctor were inspired by their exploits. (TV: Planet of the Dead, The Power of Three, The Day of the Doctor, et al.)

Jack Harkness counted those who'd even met the Doctor as lucky, (TV: Revolution of the Daleks) but Martha Jones compared the Doctor to fire, saying he was "brilliant", but getting too close meant "people get burned". (TV: The Sontaran Stratagem) Rose Tyler and Madame de Pompadour, however, agreed that "the Doctor is worth the monsters", since "you cannot have one without the other." (TV: The Girl in the Fireplace)

Joan Redfern scolded the Tenth Doctor, and had him confirm that no one would have died in Farringham if he hadn't chosen that time and place, "on a whim", while fleeing from the Family of Blood. (TV: The Family of Blood) By the Eleventh Doctor's time, the Doctor himself believed he put people in danger by involving them. Though Craig Owens believed the safest place to stand would be by the Doctor's side, both Craig and Alfie Owens were put in danger, and the Eleventh Doctor placed this on himself. (TV: Closing Time)

The First Doctor set out travelling in hopes of finding an answer to a fundamental question: how, despite all odds, good tended to triumph over evil in the universe. According to Bill Potts, the Doctor became the answer to this very question, without ever pausing to consider this. She suggested it was him "wandering around, putting everything right when it goes wrong", and that only the Doctor failed to see his own impact. Everyone else could see that, by fighting oppression wherever they went, the Doctor helped to "hold [the universe] together". (TV: Twice Upon a Time)

On Gallifrey
The Doctor belonged to the Prydonian Chapter, the most important chapter of Time Lord society. (TV: The Deadly Assassin)

Having broken the Time Lords' non-interference policy, the Second Doctor was put on trial as a renegade. (TV: The War Games) Subsequently, for a time, he acted as an agent of the Time Lords' Celestial Intervention Agency before the beginning of his sentence on 20th century Earth. (PROSE: Players, World Game) Following his defeat of Omega, which saved Gallifrey, he was granted a pardon and given his freedom. (TV: The Three Doctors) The Fourth Doctor, as part of a ploy to outwit on Gallifrey, became a candidate for the position of Lord President of the Supreme Council. While he had the right to stay and keep up the title, he left after the Master's defeat. (TV: The Deadly Assassin, The Invasion of Time)

The Doctor later returned to reclaim his title and "try out" being President, (PROSE: Doctor Who and the Krikkitmen) although in truth he had only returned only to foil the Vardans' and Sontarans' attempted invasion of Gallifrey. Afterward, he quickly left, (TV: The Invasion of Time) declaring it the worst vacation he'd ever taken. The Time Lords later reflected that the Earth had been invaded, by their count, every week during the Doctor's exile, only for Gallifrey to be invaded twice when the Doctor had arrived. As such, they were happy to see the Doctor kept away from their homeworld in the hope that they would not suffer more invasions. (PROSE: Doctor Who and the Krikkitmen) Indeed, a Time Lord messenger once admitted the Time Lords were happy to allow the Doctor his freedom to travel throughout time and space, so long as they could sometimes send him to do their dirty work, much to his annoyance. (TV: Genesis of the Daleks, Attack of the Cybermen)

The Fifth Doctor was put on trial again for recklessness. (COMIC: The Stockbridge Horror) He was later given the title of Lord President by Councillor Flavia, against his wishes. He pretended to accept the office but ran away in his TARDIS. (TV: The Five Doctors) The Fifth Doctor did later serve time in office on Gallifrey, and initiated various reforms for the Academy. (AUDIO: Time in Office) The Sixth Doctor was later deposed in absentia and put on trial for breaking the non-interference policy and later in the same trial, for genocide. The validity of this trial was called into question when it was discovered it had been orchestrated by the Valeyard, a future manifestation of the Doctor who intended to steal the Doctor's regenerations. (TV: The Trial of a Time Lord)

During the Last Great Time War, the Sisterhood of Karn revived the Eighth Doctor and offered him an elixir for regeneration precisely because they believed only the Doctor could save the universe from the Time War's devastating impact. Ohila pressured him to take a more active role, as the universe's final hope. She deplored the Doctor not to let this universe fall. (TV: The Night of the Doctor) The ensuing incarnation, the War Doctor, was beloved by the Time Lord army, as they saw that he fought side by side with them. (TV: Hell Bent, PROSE: Decoy)

During the Siege of Trenzalore, when the Eleventh Doctor was again on the verge of death, with no remaining regenerations, the Time Lords responded to Clara Oswald's plea to help him by granting the Doctor a new regeneration cycle, (TV: The Time of the Doctor) rather than allow him to die on Trenzalore, as in the original timeline. (TV: The Name of the Doctor) After returning to Gallifrey by means of his confession dial, the Twelfth Doctor stood against Lord President Rassilon, and deposed him, using the reputation he had gained with his fellow Time Lords during the Time War. Rassilon's own firing squad refused to execute him, intentionally misfiring. The Doctor then took over as Lord President to save Clara Oswald's life, before once more fleeing Gallifrey in a stolen TARDIS. (TV: Hell Bent)

In the Thirteenth Doctor's time, ravaged Gallifrey when he discovered that the Doctor's earliest incarnations had been the template for all Time Lords. The Doctor herself was responsible for killing all remaining life on the planet, in order to stop the Master's Cybermen. (TV: The Timeless Children)

The greatest enemy of the Daleks
Of the many foes the Doctor encountered and bested over their travels, their most persistent and notable enemy were the Daleks, a species of xenophobic mutants native to the planet Skaro, with the Doctor and Daleks both recognising each other as each other's greatest foe. (TV: Victory of the Daleks, COMIC: Harvest of the Daleks, Defender of the Daleks) As Darla von Karlsen once observed, "first, there were the Daleks. And then, there was a man who fought them". (TV: Asylum of the Daleks) In fact, the First Doctor's first visit to Skaro marked a change for both him and the Daleks; the Doctor was horrified by the evil of the Daleks, making the mutants the reason the Time Lord made it their mission to fight evil across time and space, (TV: Into the Dalek) while their first meeting with the Doctor proved to the Daleks that life existed on other worlds, convincing them to form the Dalek Empire to spread across the stars. (AUDIO: The Lights of Skaro)

Furthermore, the Daleks eventually learned the Fourth Doctor had been present at their genesis and nearly wiped out their species then on behalf of the Time Lords, with the Daleks viewing that action as an act of aggression that began the Last Great Time War. The Dalek Eternity Circle, however, did claim to the War Doctor that his failure to wipe them out proved to the Dalek Empire that emotion was a weakness. (PROSE: Engines of War) For their repeated stands and victories against the Daleks, the Doctor became seen as the sole reason the Daleks had yet to conquer all of creation. (COMIC: The Lost Dimension) Becoming the most hated enemy to a species that could only hate, the Daleks also appeared to showcase fear towards the Time Lord despite the Daleks having removed all trace of that emotion from themselves; the Doctor became known as the "Oncoming Storm" and "the Predator" amongst other names, with one Dalek drone reflecting that the Daleks had grown stronger in fear of their enemy. (TV: The Parting of the Ways, Asylum of the Daleks)

When all knowledge of the Doctor was erased from the Dalek Pathweb for a time, the Daleks' never-ending war against the rest of existence collapsed, with the Dalek Parliament left squabbling to figure out who their forgotten arch-enemy had been. When the Dalek race's memory of the Doctor was restored during the Siege of Trenzalore, the Prime Minister of the Daleks was left in a mortified, insane state that made the current Dalek Supreme execute it to take control of their empire. (TV: The Time of the Doctor, PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe) once reflected that, out of all of the Doctor's enemies, it was the Daleks who hated them the most, (TV: The Witch's Familiar) and the Thirteenth Doctor declared encounters with the Daleks personal affairs. (TV: Resolution) In fact, fighting the Daleks helped her to rediscover her identity as "the Doctor" after being shaken by secret truths, stating "I'm the Doctor, I'm the one who stops the Daleks". (TV: Revolution of the Daleks)

Cybermen and Sontarans
The Doctor also became a consistent enemy to the Cybermen, a race of human cyborgs who sought to survive and upgrade others to "become like [them]". (TV: Rise of the Cybermen) A Neomorph Cyber-Leader observed that the Doctor, in contrast to the Time Lords' non-interference policy, did "nothing else but interfere". (TV: Earthshock) Despite only encountering him one time prior, the Cybusmen of Pete's World quickly recognised the Doctor as an enemy, with Cyber-Leader One telling the Tenth Doctor that he was proof that emotions were destructive. (TV: Doomsday) The Twelfth Doctor once claimed that legends spread about his stands against the Cybermen, proclaiming that "There's only ever been one way to stop [a massive army of] Cybermen. Me!" (TV: The Doctor Falls)

The Sontaran Empire came to see the Doctor as their archenemy (TV: War of the Sontarans) despite their never-ending war with the Rutan Host. The Doctor was thus recognised as a priority target, although the Doctor's actions during the Time War were spread amongst the Sontarans as legends. (TV: The Sontaran Stratagem) Commander Skaak of the Sontaran Empire regarded the Doctor as "treacherous vermin". (TV: War of the Sontarans)

The Master
claimed to Clara Oswald that she had "always" cared about the Doctor and that she was their friend, that they shared a friendship older and "infinitely more complex" than Clara's civilisation. When Clara disputed her claim, noting that she had tried to kill the Doctor, Missy retorted that the Doctor had tried to kill her, likening as "sort of [their] texting" and that they had "been at it for ages". She chided Clara for the "disgusting" suggestion that they were in love, telling her to try to "rise above the reproductive frenzy of [her] noisy little food chain". (TV: The Magician's Apprentice)

Confronting the Third Doctor, admitted that he was "almost" his intellectual equal. (TV: Terror of the Autons) The once reflected that "a cosmos without the Doctor scarcely bears thinking about." (TV: The Five Doctors) Whilst evaluating the Doctor's first seven incarnations, he regarded the Third Doctor as a worthy foe, while lamenting that the Seventh Doctor's cunning and ingenuity were wasted on a "stubborn streak of goodness". (GAME: Destiny of the Doctors)

The Third Doctor introduced the Master as his "best enemy" to Sarah Jane Smith. (TV: The Five Doctors) later introduced himself to the Thirteenth Doctor's companions as such. (TV: Spyfall) The Doctor always had a great effect on the Master, to the point where Missy began to give up her dark ways and stand up for what was "kind" through a series of discussions and adventures with the Twelfth Doctor. Fully embracing the idea that it was time "to stand with the Doctor", she was killed at the hands of (TV: The Doctor Falls) but regenerated into a new incarnation who called herself "the Lumiat", embracing the new start as a way to do good in the universe, only for a younger version of Missy to kill her. (AUDIO: The Lumiat) The "Spy" Master, who returned to the dark ways that Missy and the Lumiat began to move past, (PROSE: The Doctor vs the Master, AUDIO: The Lumiat) hated the Doctor more than ever before after learning about the Timeless Child. (TV: The Timeless Children)

A universe without the Doctor
River Song believed that "all the skies of all the worlds might just turn dark" if the Doctor ever gave up on helping other people, (TV: Forest of the Dead) and Nardole once told the Twelfth Doctor that, if he died that day, "everybody in the universe might just go cold". (TV: Twice Upon a Time)

When the Great Intelligence changed time so that the Doctor's victories were negated, entire star systems began to disappear without the Doctor, (TV: The Name of the Doctor) and when a Time Beetle created a parallel world in which the Tenth Doctor died, never having met Donna Noble, Earth quickly devolved into chaos, and across the universe, the stars were going out, (TV: Turn Left) without the Doctor and Donna to stop the Reality Bomb from destroying the multiverse. (TV: Journey's End)

Origins
The Doctor had a variety of different and contradictory origins: (PROSE: Unnatural History, Celestial Intervention - A Gallifreyan Noir) most often, they had always been a Time Lord from Gallifrey, (TV: The War Games, et al.) but sometimes they had always been a human-Gallifreyan hybrid (TV: Doctor Who, et al.) or possibly a human from Earth (PROSE: Doctor Who and the Daleks, et al.) or from "some planet" the 49th century. (PROSE: Unnatural History) Sometimes, the Doctor believed they had been woven from a loom, and sometimes they believed there had been a mother and father. (PROSE: The Scarlet Empress) The Doctor could not remember which was true and which was a dream. (PROSE: The Shadows of Avalon)

All of these origins were equally and paradoxically true due to the Doctor's biodata being retroactively manipulated (PROSE: Unnatural History) by subconscious regeneration influences (PROSE: The Blue Angel) as well as powerful beings such as Omega, (PROSE: The Infinity Doctors) the enemy, (PROSE: Unnatural History) the Great Intelligence, (TV: The Name of the Doctor) and Faction Paradox. (PROSE: Unnatural History, Interference - Book Two, The Shadows of Avalon)

Overview
The Doctor left Gallifrey and became a figure who fought evil and injustice across the universe in violation of the Time Lords' non-interference policy. (TV: The War Games, Twice Upon a Time)

The Twelfth Doctor later explained to that it was his first encounter with the Daleks on Skaro which truly defined his character. (TV: Into the Dalek) In his earliest travels, the First Doctor stressed the importance of not interfering, and felt his and Susan's only responsibility was to themselves. (AUDIO: The Sleeping Blood) By most accounts, the Doctor began exploring only to experience the wonders of the universe first-hand and have some fun. In practice, he frequently became embroiled in machinations and crises that ended with him defeating the foe and saving the planet he was visiting. (TV: Gridlock, "An Unearthly Child", "A Desperate Venture") On Skaro, the Doctor first became involved, and took a stand against oppression. (TV: The Daleks) In time, he became a man he would no longer recognise. (TV: Twice Upon a Time) After much time spent alone re-thinking her identity, the Thirteenth Doctor only needed one more encounter with the Daleks to remember who she really was, no matter her origins: she was the Doctor, the person she chose to be, the woman who stopped the Daleks. (TV: Revolution of the Daleks) As the Twelfth Doctor proclaimed, he was "the man who stops the monsters", who constructed his identity in response. (TV: Flatline)

By Azure's estimation, the Doctor wanted people "to live, to breathe", (TV: The Vanquishers) as Rose Tyler understood it, in order to be able to experience the wonders of the everyday. (TV: The End of the World, The Parting of the Ways) Azure could not understand this, as life was but one form for matter, but the Thirteenth Doctor explained it well: "Because otherwise, why are we here?" (TV: The Vanquishers)

According to Robin Hood, the Doctor was a hero, born of wealth and privilege but unable to stand the plight of the oppressed, who stole a TARDIS and flew among the stars to protect those who needed outside help. However, the Doctor himself refused the title of hero. (TV: Robot of Sherwood) He instead proclaimed that he wasn't a good man or a bad man, not a hero or an officer, nor a president; instead, he was an "idiot with a box", who travelled around helping and learning. (TV: Death in Heaven)

Though he claimed to simply "be passing by" whenever he got involved, Bill Potts believed he was always helping out because the Doctor could never simply walk past and let problems go. (TV: Smile) In fact, the Doctor frequently answered distress calls, to find these opportunities, believing that:

Though ideas of responsibility, (AUDIO: The Lost Resort, TV: The Parting of the Ways, The Girl Who Died) the promise of power, (TV: The Waters of Mars) or the intellectual game of a complex scheme with parts to play (TV: The Curse of Fenric, PROSE: Nightshade, Love and War; TV: Time Heist) often led the Doctor to ignore the autonomy of others, in time the Doctor began to defer to others on matters which concerned them, (TV: Kill the Moon) as a strong believer in free will, (TV: The Lie of the Land, AUDIO: What Just Happened?) and recognised that sometimes, he needed "someone to stop him", to call him out when he was going wrong. (TV: The Runaway Bride, Partners in Crime)

For this, and to have someone to share the universe with, the Doctor took on many companions, (TV: An Unearthly Child et al.) and lost many, each time having to relearn their ways of coping (AUDIO: The Lost Resort, The Wrong Woman, The Lost) in order to move on. (AUDIO: Relative Dimensions)

Of everyone who came to travel with the Doctor, the TARDIS was their oldest and most cherished companion. She considered that she chose him when the Doctor left Gallifrey. (TV: The Doctor's Wife) The TARDIS also considered herself the Doctor's librarian, creating records of their adventures and storing them in her library, (PROSE: The Library of Time) partly in the form of the sentient Encyclopaedia Gallifreya. (PROSE: Citation Needed) The TARDIS felt that she always took the Doctor where they needed to be, though not always where they asked. (TV: The Doctor's Wife)

Early travels
After leaving Gallifrey for "many pressing reasons" (TV: Twice Upon a Time) and enjoying several adventures with his granddaughter Susan (TV: The Edge of Destruction) before landing in London 1963, the First Doctor took on his first human companions, Susan's teachers Barbara Wright and Ian Chesterton from Coal Hill School, when they discovered the TARDIS in Foreman's Yard. (TV: An Unearthly Child) One of their earliest travels brought them to the planet Skaro, where the Doctor insisted on investigating a nearby city. There, they encountered the Daleks for the first time. (TV: The Daleks) This encounter was a formative event for the Doctor, with the Twelfth Doctor later recalling that until then him calling himself the Doctor had just been a title, but after meeting the Daleks he was clear that "the Doctor was not the Daleks". (TV: Into the Dalek)

This humble beginning led to "quite the spirit of adventure", with all four growing and changing as a result of their travels and their time together. (TV: The Sensorites) Seeing as the Doctor had little control over his Ship, the group tended to bound from one destination to another, rarely looking back. As a result, they had little sense of their impact. When they did return to Skaro, a century had passed since they fought the Daleks, and they found that quite the mythology had been built around them. (AUDIO: Return to Skaro)

Eventually, the First Doctor left Susan behind on 22nd century Earth, so that she could take root, and, for once, stay somewhere long enough build a life of her own. He knew that she would object, and stay with him forever if given the chance, so he locked her out of the TARDIS, promising he would "come back" before departing. (TV: The Dalek Invasion of Earth, AUDIO: After the Daleks) Ian and Barbara left for 1964 Earth when given the chance, (TV: The Chase) although they would again become involved in the Doctor's world. (COMIC: Hunters of the Burning Stone; PROSE: The Face of the Enemy; AUDIO: The Five Companions, Sphere of Influence) From this point forward, the TARDIS was the only major constant in the Doctor's lives. (AUDIO: Relative Dimensions)

The Doctor subsequently travelled with Vicki Pallister and Steven Taylor, during which he encountered another of his people, the Monk, who meddled far more recklessly in history than the Doctor would. (TV: The Time Meddler) After Vicki chose to remain in Troy, the Doctor was aided in transporting an injured Steven back to the TARDIS by Katarina. (TV: The Myth Makers) They immediately became embroiled in a Dalek plot in the year 4000, working alongside Space Security Service agents Bret Vyon and Sara Kingdom to stop the Daleks developing the Time Destructor. In the course of the conflict, Katarina and Sara died aiding the Doctor, (TV: The Daleks' Master Plan) losses which would weigh heavily on the Doctor throughout their lives. (COMIC: Planet of the Dead, The Last Word, The Everlasting Summer, AUDIO: The Lost)

Following another tragic loss when Oliver Harper died shortly after joining the Doctor and Steven, (AUDIO: The First Wave) the pair were embroiled in the St Bartholomew's Day massacre, after which Steven briefly contemplated leaving the Doctor for good, outraged at his refusal to interfere in history. Alone, the Doctor considered whether he should return to his home planet, however Steven ultimately returned and they were joined by a new friend, Dodo Chaplet. (TV: The Massacre)

In the company of Ben Jackson and Polly Wright, the Doctor encountered the Cybermen for the first time at Snowcap in Antarctica. Once the crisis was all over however he hurriedly made for the TARDIS, (TV: The Tenth Planet) knowing his first regeneration was imminent. He was initally resistent to the change, however a chance encounter with his future self and Testimony Foundation changed his outlook to embrace the process. (TV: Twice Upon a Time)

The new Second Doctor's first adventure saw him encounter the Daleks on Vulcan, with his actions reaffirming to Ben and Polly he was indeed the same man. (TV: The Power of the Daleks) Shortly afterwards he encountered Jamie McCrimmon, who would become this incarnation's foremost friend. (TV: The Highlanders) After Ben and Polly decided to leave after the TARDIS brought them back to their home time period, (TV: The Faceless Ones) the Doctor and Jamie were embroiled in the Dalek Emperor's plan to research the Human Factor. Manipulating Jamie in the process, the Doctor manipulated the experiments to incite a civil war on Skaro, which he hoped was the Daleks' "final end". Amongst the chaos, a human scientist caught up in the experiment, Edward Waterfield, died saving the Doctor's life and asked him to look after his daughter, Victoria Waterfield. (TV: The Evil of the Daleks)

During his travels with Jamie and Victoria, the Doctor's curiosity got the better of him on Telos, where he helped a team of archeologists access a Cyber-tomb. (TV: The Tomb of the Cybermen) They subsequently encountered the Ice Warriors and the Great Intelligence for the first time. (TV: The Abominable Snowmen, The Ice Warriors) During a second battle with the Intelligence in 20th century London, the Doctor met Colonel Alistair Lethbridge-Stewart for the first time, becoming firm allies. (TV: The Web of Fear)

Shortly after Victoria left, the Doctor and Jamie encountered the Cybermen at Space Station W3 after which one of the crew, Zoe Heriot, stowed away. (TV: The Wheel in Space) The trio subsequently found themselves in the Land of Fiction, (TV: The Mind Robber) worked with newly-promoted Brigadier Lethbridge-Stewart and UNIT to stop a Cyberman invasion of Earth, (TV: The Invasion) and inadvertently altered the past of his first incarnation, which gave the Doctor an opportunity to say a proper goodbye to Katarina when he put things right. (AUDIO: Daughter of the Gods)

The Second Doctor's adventures were cut short after he was forced to call in the Time Lords to return hundreds of humans kidnapped from their own time eras by the War Lord in a scheme to create an army to conquer the galaxy. As he'd feared, the Time Lords put the Doctor on trial for his interference, which he pled guilty to though argued he had only been doing so to fight against the evils of the cosmos. The Time Lords separated him from his companions, who were returned home with only the memory of their first adventures, and sentenced him. To his surprise they accepted his plea, though still enforced a change of appearance, exile to Earth in the 20th century, and the loss of his knowledge of how to control the TARDIS. (TV: The War Games)

Before serving his complete sentence, the Second Doctor worked for the Celestial Intervention Agency. For a time he was allowed to travel, even being accompanied by Jamie again, albeit with his memories altered. (PROSE: Players, World Game) Eventually however his exile was enforced, though he escaped the change of appearance. (COMIC: The Night Walkers) Taking up residence at the Carlton Grange Hotel, the Doctor became a celebrity, (COMIC: Action in Exile, The Mark of Terror, The Brotherhood, U.F.O.) but soon faced his regeneration, at the Time Lords' behest. (COMIC: The Night Walkers)

Exile on Earth
During his exile on Earth, the Third Doctor worked for UNIT, an organisation which fought to protect the Earth against alien threats. (TV: Spearhead from Space) He worked closely with Brigadier Alistair Gordon Lethbridge-Stewart, and though he often disagreed with the Brigadier's militaristic methods, (TV: Doctor Who and the Silurians) the two developed a close friendship, disagreements and all. The Eighth Doctor regretted that he never gave the Brigadier enough credit. Looking back, the Doctor realised he had been redirecting his own frustration at feeling trapped on Earth, in one place and time. (AUDIO: UNIT Dating)

The Doctor was UNIT's scientific advisor, and foiled many alien threats — tinkering with advanced alien technology on the side — with the help of his assistant Liz Shaw, (TV: Spearhead from Space) and later, Jo Grant. While Liz was an accomplished scientist, Jo had no formal training, and the Doctor was poised to reject her out of hand. However, she proved herself early in their first encounter with, the Doctor's arch-nemesis, and a deep fondness developed between the two over time, uncovering a gentler side to him. (TV: Terror of the Autons, The Time Monster, et al.)

The Doctor found his match in the Master as an opponent, but always managed to get the upper hand. (TV: Terror of the Autons et al.) The Twelfth Doctor later characterised him as the only person "even remotely like [him]". The Master had been his closest friend on Gallifrey. Though they were now enemies, a certain kinship was never lost, (TV: World Enough and Time) and in truth, the Master often created chaos in order to get the Doctor's attention, laying traps for him, and even looking forward to his response. (TV: The Sea Devils; PROSE: Legacy of the Daleks, AUDIO: Animal Instinct; TV: Death in Heaven) Even the Doctor admitted he was "looking forward to [their] next encounter". (TV: Terror of the Autons)

The knowledge of the TARDIS was restored to him after he helped to defeat Omega, partnering up with his two other selves. (TV: The Three Doctors) Afterwards, the Doctor resumed his adventures in time and space. (TV: Carnival of Monsters) He was heartbroken by Jo's departure from UNIT, soon after. (TV: The Green Death; AUDIO: Peepshow)

The Doctor met Sarah Jane Smith near the end of his third life, (TV: The Time Warrior) forming a friendship which would last several lifetimes, (TV: Robot, School Reunion, Death of the Doctor; COMIC: Train-Flight; PROSE: Lily, Interference) and regenerated once more. (TV: Planet of the Spiders)

Wandering the fourth dimension
The Fourth Doctor continued to work for UNIT, for a time, but he became less reliable, as he began gallivanting around the universe, no longer bound to Earth. (TV: Robot, The Ark in Space, The Android Invasion, et al.) Early in the Fourth Doctor's life, he was sent by the Time Lords to prevent the creation of the Daleks, but despite having the chance he refrained from committing genocide. (TV: Genesis of the Daleks) He later had to leave Sarah Jane Smith behind when he was called to Gallifrey, (TV: The Hand of Fear) where he attempted to avert the assassination of the President and became implicated in a political plot, and in 's first major attempt to prolong his life by unnatural means. (TV: The Deadly Assassin)

He travelled for a while with Leela of the Sevateem, a "savage" woman whom he educated, and whom he learned to respect in turn. Alongside them, K9 Mark I joined the scene. (TV: The Face of Evil, The Invisible Enemy, et al.) On Gallifrey, the Doctor became Lord President. Leela and K9 stayed behind on Gallifrey, while the Doctor abandoned his new post. (TV: The Invasion of Time)

Later on, the Doctor was tasked with collecting the segments to the Key to Time, and Romana I was assigned to his operation. (TV: The Ribos Operation) On discovering that the final segment was Princess Astra of Atrios and assembling the Key, they attracted the attention of the Black Guardian, and found a new goal: preventing him from obtaining the Key, which held untold power. In order to evade him, the Doctor fitted his TARDIS with a randomiser. (TV: The Armageddon Factor)

Romana II, K9 Mark II and the Doctor became trapped in E-Space when they accidentally travelled through a CVE. On Alzarius, they met Adric, who had an impressive young mind, but much to learn, (TV: Full Circle) though, in Romana's view, the Doctor never seemed to know what to say to the child. (AUDIO: Purgatory 12) Eventually they found a way out of E-Space, though Romana and K9 opted to remain behind to help the Tharils. (TV: Warriors' Gate)

Back in normal space, the Doctor and Adric visited Traken, where they met Nyssa and encountered once more. Unknown to them after their departure, the Master stole the body of Nyssa's father, Tremas. (TV: The Keeper of Traken) He subsequently stalked the Doctor, embroiling Tegan Jovanka after killing her aunt, and eventually following him to Logopolis, where the Master's meddling led to the failure of the Logopolitans' efforts to divert entropy through CVEs. With a wave of entropy now spreading, the Doctor reluctantly agreed to work with the Master to save the universe. Together they used the Pharos Project to reopen a CVE to divert the entropy; however, the Master revealed his intent to blackmail the universe with the threat of closing it again. The Doctor foiled his plan by sabotaging the equipment, but fell from the Project's radio telescope in doing so. The Doctor regenerated into his fifth incarnation, aided by the Watcher, and in view of Adric, Tegan and Nyssa. (TV: Logopolis)

In his early days, the Fifth Doctor was mainly preoccupied with unsuccessful efforts to return Tegan to Heathrow Airport. (TV: Four to Doomsday, The Visitation) Tragedy struck during an encounter with the Cybermen, when Adric was killed foiling their plan to crash a freighter into Earth in the 26th century. (TV: Earthshock) After another encounter with the Master, the Doctor finally left Tegan at Heathrow, (TV: Time-Flight) and travelled on with Nyssa. (PROSE: Empire of Death, AUDIO: The Land of the Dead) Notably the pair became embroiled in the creation of the Cybermen on Mondas and made an ultimately futile effort to delay their development. (AUDIO: Spare Parts)

The Doctor and Nyssa were reunited with Tegan during Hedin's scheme to unleash Omega using the Doctor's biodata. After foiling Omega's return, (TV: Arc of Infinity) they resumed their travels. During this time, the Black Guardian sought his revenge on the Doctor and secretly tasked Vislor Turlough with assassinating him. Turlough joined the TARDIS crew to this end. (TV: Mawdryn Undead) After Nyssa departed, (TV: Terminus) the crew became embroiled in a race between Eternals organised by the Guardians. During this the Doctor learned the truth about Turlough and helped him stand up to the Black Guardian, allowing him to remain onboard the TARDIS afterwards. (TV: Enlightenment) The Doctor also encountered a member of the Celestial Preservation Agency, who came from a time in Gallifrey's future history where the Doctor was a cultural hero. (AUDIO: Omega)

After being embroiled in President Borusa's insane scheme to claim immortality in the Game of Rassilon, along with his previous four incarnations, the Doctor was again appointed President of Gallifrey by the High Council. He opted to run away from his new responsibilities. (TV: The Five Doctors) After he accidentally crossed the frontier in time, (TV: Frontios) the Doctor was summoned to Gallifrey to serve his term. After a short time in office, during which he pursued reforms to the Time Lord Academy, the Doctor passed the presidency onto Castellan Lowri and resumed his travels. (AUDIO: Time in Office)

Following a brutal encounter with the Daleks, Tegan opted to stay behind on Earth, believing travelling with the Doctor was no longer fun. (TV: Resurrection of the Daleks) Shortly afterwards Turlough also left to rejoin his people, leaving the Doctor in the company of Peri Brown, whom he'd saved from drowning in Lanzarote. (TV: Planet of Fire) The Doctor and Peri visited Androzani Minor, where they both contracted spectrox toxaemia. The Doctor was able to retrieve the antidote but only had enough for Peri, forcing him to regenerate to survive. (TV: The Caves of Androzani)

The Sixth Doctor endured a difficult post-regeneration period, during which he briefly attacked Peri whilst deluded into believing her a spy. (TV: The Twin Dilemma) The pair continued travelling together, with their initially frosty relationship becoming much closer, encountering Cybermen, Sil, the Rani and Davros together. (TV: Attack of the Cybermen, Vengeance on Varos, The Mark of the Rani, Revelation of the Daleks)

After stumbling onto Ravolox, the Doctor was again put on trial by the Time Lords. During this he was separated from Peri, having been moments away from saving her from having Lord Kiv's brain implanted in her. With the surprise intervention of, he discovered that the Prosecutor, the Valeyard, was a personification of his evil future self, who was helping to cover up the crimes of the High Council of the Time Lords. After defeating the Valeyard, the Doctor was assured Peri had been saved, (TV: The Trial of a Time Lord) and later learned she had multiple contradictory yet co-existing fates due to the Time Lord meddling. (AUDIO: Peri and the Piscon Paradox) In the immediate aftermath of the trial, the Doctor was reluctant to interfere but eventually resumed his travels in the company of Grant Markham. (PROSE: Time of Your Life)

The Sixth Doctor went on to travel with a wide variety of companions including Evelyn Smythe, (AUDIO: The Marian Conspiracy) Charlotte Pollard, (AUDIO: The Condemned) a fictionalised verison of Jamie McCrimmon, (AUDIO: City of Spires) Henry Gordon Jago and George Litefoot, (AUDIO: The Hourglass Killers) Flip Jackson, (AUDIO: The Curse of Davros) Constance Clarke, (AUDIO: Criss-Cross) and finally Melanie Bush, (PROSE: Business Unusual) with whom he shared an adventure which had previously been used as evidence from his future in his trial. (TV: Terror of the Vervoids) He and Mel were also joined by Hebe Harrison. (AUDIO: The Rotting Deep)

There were contradictory accounts as to the cause of the Sixth Doctor's regeneration. One suggested it had been due to his next incarnation influencing him to ensure he might come into existence sooner, (PROSE: Head Games) another as a consequence of his battle against the Lamprey alongside numerous parallel counterparts of himself, (PROSE: Spiral Scratch) and a third as part of a scheme to foil the Valeyard's master plan to usurp Time Lord civilisation. (AUDIO: The Brink of Death) Regardless of the cause, all accounts agreed the TARDIS fell into a trap set by the Rani, who entered the ship just as the Doctor regenerated into his seventh incarnation. (TV: Time and the Rani)

Time's Champion
Though initially a jovial character in the company of Mel, (TV: Paradise Towers, Delta and the Bannermen) the Seventh Doctor darkened over time. (PROSE: Just War, AUDIO: The Fires of Vulcan) Whilst visiting Iceworld, he and Mel met Ace, a teenager from the 20th century displaced in time by a time storm. (TV: Dragonfire) Recognising the influence of Fenric on her, (TV: The Curse of Fenric) the Doctor let her come with him whilst Mel chose to stay behind with Sabalom Glitz. (TV: Dragonfire)

Adopting a more proactive approach, the Doctor ended the Imperial-Renegade Dalek Civil War by setting a trap with the Hand of Omega, (TV: Remembrance of the Daleks) saw to the overthrow of Helen A on Terra Alpha, (TV: The Happiness Patrol) and disposed of the Nemesis and the factions fighting over it. One of those involved in the fight for the Nemesis, Lady Peinforte, learned secrets about the Doctor through the statue (TV: Silver Nemesis) and a "place of knowledge" called TARDIS Wiki. (PROSE: Lady Peinforte) As he'd suspected, Fenric returned and the Doctor was forced to break Ace's faith in him to enable the Ancient One to move against Fenric. (TV: The Curse of Fenric)

After encountering once more, (TV: Survival) the Doctor and Ace continued travelling together. There were multiple possible outcomes of their travels, including Ace growing old in the Doctor's company, (PROSE: At Childhood's End) Ace dying in his arms after fighting the Lobri, (COMIC: Ground Zero) Ace leaving his company to become Time's Vigilante, (PROSE: Set Piece) and the Doctor sending her to Gallifrey. (AUDIO: Intervention Earth) By one account after witnessing these possible fates via the quantum anvil and growing angry at the Doctor's scheming, Ace asked the Doctor to take her home. (PROSE: At Childhood's End) A similar account also suggested they simply fell out eventually. (TV: The Power of the Doctor)

As recalled by the Eighth Doctor later in his life the Seventh Doctor ended up travelling alone, unable to trust himself with others' lives. (AUDIO: The Resurrection of Mars) In this lonely phase of his life, the Doctor made a deal with Death to try to save the Master, (AUDIO: Master) built himself a robotic companion, Catherine Broome, (PROSE: Companion Piece) and tied up loose ends including Elizabeth Klein, (AUDIO: A Thousand Tiny Wings) and Mags. (AUDIO: The Monsters of Gokroth)

Life's Champion
As ordered by the Time Lords, (PROSE: Lungbarrow, The TV Movie) the Doctor collected the Master's remains for return to Gallifrey following his execution by the Daleks. En route, the Master, who had survived using a Deathworm Morphant, (AUDIO: Mastermind) sabotaged the TARDIS console causing the ship to make an emergency landing in the midst of a gang war in San Francisco. Upon exiting the TARDIS, the Doctor was gunned down and subsequently taken to hospital. Confused by his alien anatomy, Dr Grace Holloway inadvertently caused his hearts to stop. The Doctor regenerated later that night in the hospital's morgue, the process having been delayed by the anaesthetic in his system.

Though initially suffering amnesia, the newly regenerated Eighth Doctor managed to regain his identity and defeated the Master's plan to use his TARDIS' Eye of Harmony to steal his body. (TV: Doctor Who) He resumed his travels with a more optimistic outlook, sometimes styled as Life's Champion. (PROSE: Vampire Science, AUDIO: Light the Flame) He initially travelled with Sam Jones, (PROSE: The Eight Doctors) but left her at a Greenpeace rally and went travelling alone for some years. (PROSE: Vampire Science) During this time his main companion was Izzy Sinclair, with whom he tied up loose ends regarding the Threshold, and the Master during his attempt to seize the Glory, being aided by Fey Truscott-Sade and Kroton respectively. (COMIC: Wormwood, The Glorious Dead)

Resuming his travels with Sam, the Doctor began to encounter parts of the looming War in Heaven, including Faction Paradox, (PROSE: Alien Bodies) and was joined by Fitz Kreiner. (PROSE: The Taint) After Sam departed, they were joined by Compassion, (PROSE: Interference) whose signal receiver the Doctor linked to the TARDIS. (PROSE: The Taking of Planet 5) This inadvertently caused her to evolve into a sentient TARDIS. After his TARDIS was seemingly destroyed, the Doctor and Fitz began travelling within her, pursued by the Time Lords who wished to exploit her in preparation for the War. (PROSE: The Shadows of Avalon) The Time Lords eventually tracked them down, (PROSE: The Banquo Legacy) just as the outbreak of the War approached and Faction Paradox invaded Gallifrey. Discovering his old TARDIS had become the Edifice, the Doctor used it to destroy Gallifrey to prevent the War and stop Faction Paradox. (PROSE: The Ancestor Cell) With Compassion's help, he saved the Time Lords by copying all their minds from the Matrix, suppressing his own memories. (PROSE: The Gallifrey Chronicles) Compassion retrieved Fitz and the remains of the TARDIS and took the amnesiac Doctor to Earth in 19th century, leaving a note to meet Fitz in 2001 by which time his TARDIS would have recovered. (PROSE: The Ancestor Cell)

After a century living on Earth, (PROSE: The Burning, Casualties of War, The Turing Test, Endgame, Father Time) the amnesiac Doctor reunited with Fitz and resumed travelling in the recovered TARDIS, being joined by Anji Kapoor. (PROSE: Escape Velocity) They repeatedly battled Sabbath, (PROSE: The Adventuress of Henrietta Street, Time Zero) and were joined by Trix MacMillan. (PROSE: Timeless) They finally confronted Sabbath's employers, the Council of Eight, and defeated them. (PROSE: Sometime Never...) Not long afterwards the Doctor encountered a surviving Time Lord, Marnal, and learnt the cause of his amnesia. Intending to restore the Time Lords, he first faced the Vore invasion of Earth. (PROSE: The Gallifrey Chronicles)

By rescuing Charlotte Pollard from her fate on the R101 and allowing her to travel with him, (AUDIO: Storm Warning) the Doctor damaged the Web of Time, creating an opportunity for anti-time to contaminate the universe. He was forced by President Romana to join the Time Lords' expedition to the antiverse to stem the flow and ultimately saved Gallifrey from the Neverpeople's plan to destroy the Web of Time. (AUDIO: Neverland) In the process he was contaminated by anti-time and had to exile himself to a Divergent Universe to prevent damage to time. (AUDIO: Zagreus)

To his annoyance, Charley joined him against his wishes, putting herself in danger all over again when he'd just finished saving her. (AUDIO: Scherzo) Together they explored the divergent universe, being joined by C'rizz, (AUDIO: The Creed of the Kromon) until they discovered a way back to the main universe, and confirmed that he was free of anti-time. (AUDIO: The Next Life) Tragedy struck not long afterwards when C'rizz was killed, (AUDIO: Absolution) prompting Charley to demand to go home. Due to complications arising from an encounter with the Cybermen, the Doctor was left believing she was on Earth in 2008 when she was actually stranded in 500002, only to be rescued by the Sixth Doctor. (AUDIO: The Girl Who Never Was)

The Eighth Doctor travelled with Destrii. (COMIC: Sins of the Father) They encountered an advanced force of Cybermen from the far future in 2005, during which the Doctor briefly bonded with the Time Vortex to save the Earth by wiping out the Cyber-Army. Although the Vortex called to him with the offer of an immortal existence, he rejected the offer to save Destrii. (COMIC: The Flood)

The Eighth Doctor later travelled with Lucie Miller, initially as part of a forced Time Lord witness protection scheme and eventually by choice. (AUDIO: Blood of the Daleks, Human Resources) They were separated after a confrontation with Morbius, (AUDIO: The Vengeance of Morbius) during which the Doctor spent centuries living on Orbis. (AUDIO: Orbis) Resuming their travels, Lucie eventually left his company after discovering he'd lied to her about the death of her aunt Pat. (AUDIO: Death in Blackpool) The Doctor subsequently reconnected with Susan, meeting his great-grandson Alex Campbell, (AUDIO: An Earthly Child) and travelled with Tamsin Drew, (AUDIO: Situation Vacant) until an encounter with the Monk reunited him with Lucie whilst Tamsin chose to travel with the Monk instead. (AUDIO: The Resurrection of Mars)

In a brutal battle with the Daleks, the Doctor witnessed the deaths of Tamsin, Alex and Lucie. He furiously dismissed the Monk after discovering his role in enabling the Daleks and delaying his arrival, and travelled on alone. (AUDIO: To the Death) Desperate for hope, he ran to the end of the universe. He reluctantly accepted a mission from the Time Lords to look after Molly O'Sullivan and battled the Dalek Time Controller. He subsequently became embroiled in 's scheme to exploit the Eminence and was joined by Liv Chenka. (AUDIO: Dark Eyes)

The Doctor and Liv travelled together for some time before battling the Doom Coalition assembled by Cardinal Padrac to destroy the universe. They were joined by Helen Sinclair and discreetly aided by River Song, who was aware the Doctor was too young to meet her. In the aftermath of Padrac's defeat, they went in search of Helen, who had been lost in time. (AUDIO: Doom Coalition) Retrieving Helen, the trio subsequently encountered the Ravenous and stopped the Eleven's plan to exploit them. The TARDIS was critically damaged by the Ravenous, (AUDIO: Ravenous) leaving the Doctor, Liv and Helen stranded in London in 2020 whilst it recovered. (AUDIO: Stranded)

Later in his life, the Eighth Doctor travelled with Josephine Day, (COMIC: The Pictures of Josephine Day) and became embroiled in the crisis caused by his future self. (AUDIO: The Enemy of My Enemy)

An impossible choice
As the Last Great Time War between the Time Lords and the Daleks spread, turning time upside down, the Eighth Doctor vowed to help victims from the sidelines, but refused to take part. (TV: The Night of the Doctor, AUDIO: The Starship of Theseus, et al.) He died in a spaceship crash on Karn, trying to save someone who despised him as a Time Lord. When the Doctor was revived by the Sisterhood of Karn, and given an elixir for regeneration, he agreed to become a warrior. (TV: The Night of the Doctor)

In his new incarnation, the Doctor actively fought in the Time War. Initially he served as a free agent, appearing on battlefronts across the cosmos at his own whim, (AUDIO: Forged in Fire, COMIC: Ambush) though later he fought alongside the Time Lords, answering to Cardinal Ollistra. (AUDIO: Only the Monstrous) He became famous among the Gallifreyan soldiers as he fought alongside them, (TV: Hell Bent) and his exploits in the War were legends among the Sontarans. (TV: The Sontaran Stratagem)

Later in the War, the Doctor began to turn against his own people. He foiled Gallifrey's alliance with Technomancers by wiping them out, after discovering the Technomancers were exploiting it to resurrect the Horned Ones. For this Ollistra branded him a war criminal. (AUDIO: Legion of the Lost) He continued to serve Ollistra for a time, (AUDIO: Agents of Chaos) until they fell out when he suggested the Enigma should wipe out both sides to finally end the War, a suggestion the entity ultimately didn't act on. (AUDIO: The Enigma Dimension) Finally the Doctor turned on the Time Lords after discovering Rassilon's plan to destroy the Tantalus Eye, during which Cardinal Karlax gunned down Cinder, a human whom the Doctor had befriended. Foiling both the Time Lord and Dalek plans for the Eye, the Doctor swore to finally end the War in Cinder's honour, swearing there would be "No More". (PROSE: Engines of War)

In the War's final days, the War Doctor was at the Fall of Arcadia and stole the Moment, the last weapon in the Omega Arsenal, intent on using it to destroy Daleks and Time Lords together. The conscience of the weapon decided to show him two of his future selves, to see what he would become, and after an adventure together establishing peace between UNIT and Zygons, the three Doctors realised that they had devised another way to end the War. (TV: The Day of the Doctor)

With the help many other incarnations, with the Twelfth Doctor admitting he was not sure how many Doctors united to prevent the Fall of Gallifrey, (PROSE: The Day of the Doctor) the War Doctor placed Gallifrey into a pocket universe instead, annihilating the Daleks bombarding the planet from orbit in their own crossfire. This caused the near-extinction of the Daleks. The War was sealed in a time lock, (TV: The Day of the Doctor) making it impossible to time travel back to save Gallifrey, (TV: The Stolen Earth, Father's Day) as much as the Doctor would desperately want to return. (AUDIO: The Wrong Woman)

Due to the timelines being out of sync, the War Doctor lost all memory of having saved Gallifrey rather than destroying it, so that future incarnations would believe they had been responsible for its end. Only the Eleventh Doctor retained memory of this changing narrative. Going on his way, the War Doctor found himself regenerating, remarking that he was "wearing a bit thin". (TV: The Day of the Doctor)

Last of the Time Lords
The Ninth Doctor believed that he had destroyed Gallifrey, wiping out both the Daleks and Time Lords, (TV: Dalek, The Day of the Doctor, COMIC: Don't Step on the Grass) and chose to travel alone for a time, (AUDIO: Way of the Burryman) deciding he "didn't need companions or friends". (PROSE: The Eyeless) In truth, he wished to punish himself for surviving. (PROSE: Meet the Doctor) During this time, he dealt with relics from the Time War, (AUDIO: The Oncoming Storm, Her Own Bootstraps) prevented the escape of the Ravagers, (AUDIO: Ravagers) made peace with a new race of Cybermen, (AUDIO: The Forth Generation) and was present at the assassination of John F. Kennedy, (PROSE: Have You Seen This Man?, TV: Rose) and the sinking of the RMS Titanic. (TV: The End of the World)

After meeting her whilst battling the Nestene Consciousness, the Doctor invited Rose Tyler to travel with him, asking that she was sure before allowing her to enter his dangerous life. (TV: Rose) Together they witnessed the final destruction of Earth, (TV: The End of the World) and foiled alien threats alongside Charles Dickens (TV: The Unquiet Dead) and Harriet Jones. (TV: World War Three)

Rose helped the Doctor to become a better version of himself – by his own admission – by challenging him. He was the product of war, fuelled by anger and revenge, (TV: Journey's End) saving the world out of obligation, (TV: Rose, PROSE: The Day of the Doctor) but bent on making someone pay for all this suffering. When he was brought face-to-face with the last surviving Dalek, the Doctor was made to confront his anger when Rose brought out a more human side to the Dalek. She stopped him from destroying the Dalek, to "finish the job" by assuring no survivors. (TV: Dalek)

Adam Mitchell briefly joined them, but was abandoned at home when he tried to use time travel for personal gain, (TV: The Long Game) creating a powerful grudge which would lead to Adam's ultimate revenge. (COMIC: Mystery Date) Later, the Doctor and Rose met the time-travelling con artist Jack Harkness, who joined them in the TARDIS for the rest of their time together. Jack had experience as a Time Agent, (TV: The Doctor Dances) and the Doctor would frequently remind him he was the one who made the plans. (TV: Boom Town) Finally, their travels came to an abrupt end when they were intercepted by the Game Station in 200100, (TV: Bad Wolf) where the Dalek Emperor had amassed a new Dalek fleet, having survived the Time War.

In the ensuing Battle of the Game Station, the Doctor manipulated Rose into getting sent back to London, where she'd be safe, and planned to use a Delta wave to destroy all proximal lifeforms, including humans. Unwilling to let her life with the Doctor go, Rose managed to pilot the TARDIS by looking into the heart of the TARDIS, becoming Bad Wolf. Rose showed the Doctor, even with all the power of time at her disposal, to favour life. (TV: The Parting of the Ways, Utopia) The Doctor saw that she was "so human", (TV: Utopia) and developed somewhat of a fascination with the human race in his next incarnation, (TV: New Earth) a drastic change from the Ninth Doctor's early attitude. (TV: Rose, The Unquiet Dead)

With the energy about to kill her, the Doctor took this power upon himself, forcing him to regenerate to survive. (TV: The Parting of the Ways) In his tenth incarnation, the Doctor continued travelling with Rose, (TV: The Christmas Invasion) until the Battle of Canary Wharf separated them, with Rose becoming trapped in a parallel universe. This was also the fall of Torchwood One, (TV: Doomsday) the London branch of an organisation started by Queen Victoria to capture the Tenth Doctor, an enemy of the British Empire. (TV: Tooth and Claw)

The weight of being the last of their people still weighed heavily on the Tenth Doctor, (TV: School Reunion, Gridlock, Last of the Time Lords) with the Moment branding him as "the man who regrets". Whilst the guilt of the Time War did drive him to do good, (TV: The Day of the Doctor) the War's legacy also emboldened him to recklessly callous behaviour at times. Donna Noble believed he needed someone by his side to tell him when to stop after witnessing his ruthless defeat of the Racnoss and getting him to stop, (TV: The Runaway Bride) saving his life in doing so. (TV: Turn Left)

Though reluctant to take on companions after losing Rose, the Doctor took Martha Jones with him on a "one trip" basis after she saved his life. (TV: Smith and Jones) The one trip soon became extended to multiple travels, and eventually he embraced her as a proper companion. (TV: The Lazarus Experiment) While travelling with Martha, the Tenth Doctor rediscovered on Malcassairo, hiding out at the end of the universe as the human Professor Yana, under a Chameleon Arch. Regenerating by the hand of Chantho, the professor's faithful assistant, the stole the Doctor's TARDIS (TV: Utopia) and retrofitted it into a paradox machine. On Earth in 2008, the Master set himself up as Prime Minister of the United Kingdom, taking the name Harold Saxon. (TV: The Sound of Drums)

In the Year That Never Was, the Master unveiled the Toclafane, (TV: The Sound of Drums) who were the final remnants of humanity, ripped from Professor Yana's planned journey to Utopia. (TV: Last of the Time Lords) He decimated the Earth's population, (TV: The Sound of Drums) and sent the rest into hiding. While the Doctor was trapped on board the Valiant as the Master's prisoner, and made to show his years, Martha was tasked with spreading the word, travelling all around the Earth to tell people about the Doctor. When the time came, the combined power of humanity, sharing a single thought, amplified by the Master's own Archangel Network, restored the Doctor to full health.

The decommissioning of the paradox machine by Jack Harkness reversed time to the moment it was activated. The Doctor prepared to take the Master onboard, as he felt responsibility toward him, as "the only two left" among the Time Lords. However, Lucy Saxon, the Master's wife, shot him on board the Valiant, and the Master refused to regenerate, as a final act of rebellion to hurt the Doctor. (TV: Last of the Time Lords)

After Martha left of her own accord, (TV: Last of the Time Lords) the Doctor reunited with Donna Noble, accepting her as a companion out of a desire for a mate without complications. (TV: Partners in Crime) The pair travelled together for a time. Notably, they freed the Ood from centuries of servitude, restoring the telepathic Ood Brain which bound them together, (TV: Planet of the Ood) leading to a Golden Age on the Ood Sphere. (TV: The End of Time) In Pompeii, Donna convinced the Doctor to save just one family, (TV: The Fires of Pompeii) teaching him an important lesson he would carry in his future travels. (TV: The Girl Who Died)

After escaping a catastrophic parallel universe in which she had never met the Doctor, by travelling back in time to restore the timeline, ensuring she would turn left as before, Donna passed on a message from Rose Tyler, who had visited her world. The Doctor understood "Bad Wolf" to mean the end of the universe, (TV: Turn Left) and on visiting Earth, experienced its mysterious disappearance from right beneath the TARDIS. Earth had been stolen by Davros, and taken to the Medusa Cascade, where it would be used as part of a formation designed to power the Reality Bomb. (TV: The Stolen Earth)

The Doctor joined up with many of his former companions, including Sarah Jane Smith, to defeat Davros and the Daleks. He inadvertently created the Meta-Crisis Tenth Doctor when he channeled regeneration energy into his "spare hand", to avoid complete regeneration. In the process, Donna also achieved a partial biological meta-crisis, gaining access to her own version of the Doctor's mind. All the Doctor's allies, including the Meta-Crisis Tenth Doctor, were instrumental in ending this crisis. After leaving Davros and the Daleks to burn, the Doctor and his friends piloted the TARDIS to bring Earth back to its original co-ordinates. (TV: Journey's End)

One consequence of this whole affair was that the Doctor was forced to erase all of Donna's memories of their time together, in order to preserve her life. The Meta-Crisis Doctor was left on Pete's World with Rose Tyler, (TV: Journey's End) with various sources disagreeing on all that followed for him. (PROSE: The Turning of the Tide, COMIC: Empire of the Wolf)

In light of Donna's fate, the Doctor resolved to travel alone to avoid further pain. (TV: Planet of the Dead) He took it upon himself to change history and save Adelaide Brooke from the Flood on Mars, even though her death was a fixed point in time. He burdened her with the task of influencing her granddaughter, Susie Fontana Brooke, to explore the stars, since Adelaide's death was originally her inspiration. With the Time Lords gone, he saw himself as the Time Lord Victorious, the victor, the decider of fates, no longer content to obey the Laws of Time, when he had the power — and perceived justification — to change things however he saw fit.

Adelaide rejected the Doctor's new turn towards power, and killed herself on Earth, in order to restore the chain of events which would see humanity spread out (TV: The Waters of Mars) and outlive their home planet. (TV: New Earth) Fleeing a summons from Ood Sigma he believed heralded his death, (TV: The Waters of Mars) the Doctor travelled to the Dark Times where he became embroiled in the Kotturuh crisis. He became convinced that stopping the Kotturuh spreading death would change the future for the better, eventually wiping them all out and reclaiming the title Time Lord Victorious. (PROSE: The Knight, the Fool, and the Dead)

Intervention by two of his previous selves, and an encounter with Inyit, who had become the last of the Kotturuh, showed the Tenth Doctor he had gone too far. This had devastating consequences. After stopping the Dalek Time Squad from exploiting the crisis he'd created to wipe out Gallifrey, he agreed to stop changing history and left the Dark Times. (PROSE: All Flesh is Grass)

Dreading his own demise, he distracted himself with more lighthearted destinations, still unwilling to let go. (TV: The End of Time) In the end, the Doctor learned there was no "winning", and that survival came at a cost. All he had done, all the terrible decisions he had had to make to reach the end of the Time War, strengthened his resolve to make sure "no one else [would] ever have to feel this pain." (TV: The Zygon Inversion) By the end of his twelfth incarnation, the Doctor understood that he did what he did only because it was kind, because it was the decent response to do what he could, to stand for others, no matter the consequences. (TV: The Doctor Falls)

Moving forward
The Tenth Doctor saw his end saving Wilfred Mott, after preventing Rassilon from escaping the Time War and enacting his Final Sanction, which would rip the Time Vortex apart and leave only the Time Lords, ascendent, to become creatures of pure consciousness. (TV: The End of Time) When the time came, he revisited all his old companions, as his final reward, before regenerating, to become someone new again. (TV: The End of Time, Death of the Doctor)

In his new incarnation, the Doctor crashed landed in Amelia Pond's garden and became intrigued by a crack in time in her wall. Promising he would come back, the Doctor took his TARDIS on a short trip to the near future, but arrived twelve years too late, gaining his new companion a premonitory monicker, "the girl who waited". In the intervening years, Amy had grown up, and lost faith in the Doctor's fairy tale. Together, they worked to stop Prisoner Zero and prevented the Atraxi from destroying the Earth in pursuing them. (TV: The Eleventh Hour)

Intrigued by the idea that the crack in her wall might have eaten away at Amy's history, (TV: The Big Bang) the Doctor invited her on board, finally fulfilling his initial promise. (TV: The Eleventh Hour) They were later joined in the TARDIS by Rory Williams, whom she planned to marry on the following day, with all these adventures being contained within that final night. (TV: The Vampires of Venice) Together they encountered many more of these impossible cracks, and soon discovered that these were the result of an unimaginable explosion which would destroy the universe on 26 June 2010. (TV: Flesh and Stone, The Vampires of Venice, Cold Blood)

The Doctor was lured into a trap by the Pandorica Alliance, along with River Song, in Roman Britain. Above Stonehenge, a large number of the Doctor's enemies, including Daleks, Cybermen, and Sontarans, had unified in an attempt to prevent the end of the universe — by containing the Doctor — reasoning it would be the Doctor's TARDIS at the heart of the explosion. Trapped within the Pandorica, the Doctor was unable to prevent what followed. River Song piloted the TARDIS, being dragged off course to the temporal explosion's coordinates. (TV: The Pandorica Opens) Earth became the only remaining planet in the universe at the eye of the storm. The Doctor used a paradox to arrange his own release from the Pandorica, and soon devised a plan for "rebooting" the universe. In Big Bang Two, the preserved remains of the original universe were re-released like spores when he piloted the Pandorica right into the heart of the explosion. He was successful, but was erased from time himself in the process. (TV: The Big Bang) Seeing his own time stream reverse, he decided to take his leave on the night Amelia Pond began waiting for him. The Doctor resigned himself to becoming a story in a vague memory, long forgotten, somberly noting, "We're all stories in the end." However, the Doctor was able to influence a young Amelia to remember him on her wedding night, and made his return to the universe. (TV: The Big Bang, Flesh and Stone)

According to most records, the Doctor then "died" in his eleventh incarnation at 1103 years old on 22 April 2011, when River Song appeared in an astronaut suit and seemed to kill him, creating a fixed point in time. (TV: The Impossible Astronaut) However, the Doctor avoided this death by having the Teselecta take on his form, tricking the universe into believing that the Doctor was dead. (TV: The Wedding of River Song) After this, the Doctor tried to "lay low" for a while, going as far as to delete himself from every database in the universe, (TV: The Angels Take Manhattan) to soften the blow of the impact he had been having. (TV: Asylum of the Daleks) He felt he had gotten "too big". (TV: The Angels Take Manhattan)

The Doctor briefly "retired" from travelling and refused to take on companions, (TV: The Snowmen) after losing his long-time friends, Amy Pond and Rory Williams, (TV: The Angels Take Manhattan) but began travelling with Clara Oswald, determined to uncover the mystery she represented. The Doctor had met Clara twice before, but she had led other lives, in other times and places. (TV: The Bells of Saint John, Journey to the Centre of the TARDIS)

The Eleventh Doctor's final stands
In the original timeline, the Doctor's grave was on Trenzalore, where he died in a great battle. The Doctor was buried in his TARDIS. Instead of a body, the TARDIS contained the Doctor's time stream, manifesting as a column of light. The Great Intelligence forced the Eleventh Doctor to go to Trenzalore to open the TARDIS by speaking his name, ultimately uttered by the data ghost of River Song. The Great Intelligence entered the timestream to alter the Doctor's history, but the Doctor was saved by Clara, who scattered herself across his timeline, helping the Doctor many times in all his lives, and, in this account, even suggesting the Doctor's TARDIS over another as he first fled Gallifrey. (TV: The Name of the Doctor)

After believing for four hundred years that he had destroyed his own people, the Doctor finally learned the truth when the Moment united the War, Tenth and Eleventh Doctors in an effort to change the War Doctor's mind about destroying the Time Lords to save the universe.

This encounter gave the Doctor a new perspective on his war incarnation; he came to realise that the War Doctor was "more the Doctor" than any of them, as he was somehow the Doctor "on the day it was impossible to get it right". (TV: The Day of the Doctor) Finally, the Doctor retained the knowledge that he had saved the Time Lords. The Doctor had this, at least, as he faced his approaching death on Trenzalore. (TV: The Day of the Doctor, The Time of the Doctor)

When the Time Lords sent out a signal from Trenzalore, through the final crack in space-time, the Doctor answered the call, as so many others had. He survived through the Siege of Trenzalore, standing his ground in the town of Christmas for centuries, and protecting it against the likes of the Daleks, Cybermen, Weeping Angels, and Sontarans.

Finally, he was granted a new regeneration cycle. The Doctor was ready to lose to the Daleks, as he had grown old and weary, and had no more lives left, but found a new lease of life, and, remembering what he thought of "the rules", wiped them out with his regeneration energy. In doing so, he changed the future. (TV: The Time of the Doctor)

Return to Gallifrey
The Doctor regenerated in his TARDIS and began his new regeneration cycle, pausing beforehand to call Clara Oswald at a later point in time, to remind her this new Doctor was still him, and would need her help. (TV: Deep Breath; The Time of the Doctor) The Doctor's relationship with Clara deepened, and he began to feel responsible for her, frequently mentioning a "duty of care", (TV: Under the Lake, The Girl Who Died) echoing Clara's own use of this term to describe her responsibility for her students. (TV: Kill the Moon)

He worried she would be hurt if they continued to be reckless, (TV: The Girl Who Died) and when she died, having put her life in danger for a chance to save Rigsy, (TV: Face the Raven) the Doctor spent billions of years in an effective teleportation-aided time loop, trapped in his own confession dial, mourning over her. (TV: Heaven Sent, Hell Bent) The Doctor was expected to reveal his secrets, and was placed in the confession dial by the Time Lords, who sought to find out what he knew of the Hybrid. (TV: Face the Raven, Heaven Sent)

Rather than give in, he continually engineered the circumstances so that, on the next loop, he would again punch the azbantium crystal wall – 400 times the strength of a diamond, and 20 feet thick – which would be his way out. (TV: Heaven Sent) Each time, the cycle killed him, but he fought for the chance to rescue Clara from her demise, and would not give in. (TV: Heaven Sent, Hell Bent) In the end, he ruptured the wall, and walked through onto his home planet Gallifrey. (TV: Heaven Sent)

Here, he took over and deposed Rassilon, whom he sent into exile, building on the respect and trust the War Doctor had built with his compatriots during the Time War. Finally, he manipulated the General into bringing Clara back from the moment before her death, and caused him to regenerate while they escaped. (TV: Hell Bent) Taking her to the end of the universe, the Doctor finally realised that the lengths he had gone to, to bring Clara back even after losing her for good, showed how dangerous this relationship had become. They agreed that one of them should be made to forget the other. In the end, the Doctor's memories of Clara were erased. Afterwards, Clara went her own way, taking her own TARDIS with her. (TV: Hell Bent)

Revisiting an old friendship
The Twelfth Doctor was given guardianship of the Vault, containing as prisoner, after he made an oath to protect the chamber for a thousand years. (TV: Extremis) He took to teaching at St Luke's University, becoming known for his fascinating but off-book lectures on a variety of topics. (TV: The Pilot) Earth-bound once more, he was joined by Nardole, who often reminded him of his duties, (TV: Extremis, Thin Ice, Oxygen) and eventually took on Bill Potts as her private tutor, seeing something in her which he thought they could build together. Bill became interested in his real life, and he began taking her on trips in the TARDIS. (TV: The Pilot)

The Doctor's hope for a better relationship with Missy eventually overcame his mistrust for her, and he began allowing her to leave the Vault and remain within the TARDIS, performing maintenance duties. (TV: The Eaters of Light) Missy had committed at the start to learning how to become "good", (TV: Extremis) and she claimed she was trying to change for the better. (TV: The Lie of the Land) He wanted to believe they could be friends again. (TV: The Eaters of Light, World Enough and Time) The Doctor sent Missy out with his companions, Bill and Nardole, on a trial adventure, so she could prove herself. They arrived on a Mondasian colony ship heading toward a black hole. Bill was fatally wounded, and taken below decks, where Missy’s previous self, made sure she was converted into a Cyberman. Due to time dilation, the Doctor arrived too late, (TV: World Enough and Time) and faced an army of Cybermen alongside the two Masters. (TV: The Doctor Falls)

Missy intended to join the Doctor in his last stand, but never made it, as she was fatally shot by the Master, whom she killed in turn. The Twelfth Doctor met his end in his last stand for kindness, attempting against all odds to save those around him. (TV: The Doctor Falls) He regenerated after meeting the First Doctor, who helped him realise he should always carry on, even if it meant becoming someone new. (TV: Twice Upon a Time)

Forgotten memories
Now in a female form, the Doctor met three new friends, Ryan Sinclair, Graham O'Brien and Yasmin Khan, in Sheffield. (TV: The Woman Who Fell to Earth) Calling themselves Team TARDIS, the Doctor travelled with her newfound family for a time, facing up against the Stenza Tzim-Sha, (TV: The Battle of Ranskoor Av Kolos) the Daleks, (TV: Resolution) and a new incarnation of. She found that the Master had ravaged Gallifrey. Though she had tried to keep her past behind her, sharing almost nothing about herself with her new friends, (TV: Spyfall) the Doctor was soon confronted with a mysterious past incarnation of herself, whom she did not remember, (TV: Fugitive of the Judoon) and found herself back on Gallifrey, where the Master revealed the secret of the Timeless Child. (TV: The Timeless Children)

The Doctor learned that her story was not her own, that she was once the child that Tecteun used as template for the Time Lords, and in fact came from somewhere beyond the Boundary, rather than Gallifrey. The Timeless Child, later the Doctor, was involved with the Division, who robbed them of their memories, from before they became the First Doctor. (TV: The Timeless Children)

The Doctor grappled with these revelations, and resolved questions of her identity during another battle with the Daleks on Earth: she was the Doctor, the person she had chosen to become. (TV: Revolution of the Daleks) She continued to investigate the Division in her travels. During the Flux incident, in which space itself threatened to come undone, the Ravagers returned, to play their part in unravelling time. At the Temple of Atropos, the Doctor learned the role she had played in ending the Dark Times. Within her time stream, the Doctor relived the Siege of Atropos from the Fugitive Doctor's point of view. (TV: Once, Upon Time) Finally, she was recalled to Division Control by the Weeping Angel Extraction Squad, (TV: Village of the Angels) and met a new incarnation of Tecteun. She expressed anger at her newfound guardian for having stolen her away, believing that she might have lived a whole other life as the Timeless Child if not for Tecteun and Gallifrey. (TV: Survivors of the Flux)

Tecteun revealed that the Flux was her design, intended to end this universe whilst the Division crossed over into another, specifically in order to quell the Doctor's influence on the multiverse. She also showed the Doctor the biodata module containing her stolen memories, before being killed by Swarm, who had infiltrated their base. (TV: Survivors of the Flux) Swarm showed the Doctor inside her lost memories, but wrought destruction on what remained, out of revenge. Afterwards, the Doctor narrowly averted the endtimes by teaming up with her splintered selves. Swarm and Azure attempted to offer her up as a sacrifice to Time, but as they had failed, Time took them, instead. Taking the Doctor's form, the embodiment of Time gave warning to the Doctor, telling her to "beware the forces that mass against [her]". (TV: The Vanquishers)

Time's prophecy was fulfilled when the Master revealed his survival and worked with the Daleks and Cybermen in an elaborate trap for the Doctor. Using technology pilfered from Gallifrey, he used a forced regeneration to take the Doctor's body and identity for himself. From within the subconscious the Thirteenth Doctor resisted his takeover, encouraged by manifestations of past Doctors in the form of Guardians of the Edge. With the aid of an AI hologram the Doctor had designed for a scenario where she'd died, Yaz worked with Vinder to force the Master to reverse the process. After the Doctor saw to the ruination of his allies' plans, the wounded Master caught up with her and exploited the Qurunx to strike a final fatal blow. Parting ways with Yaz, the Thirteenth Doctor regenerated alone.

The new Doctor was shocked to find himself identical in appearance to the Tenth Doctor. (TV: The Power of the Doctor) Setting off to see what the universe had in store for him, he first encountered the Daleks at the 1966 World Cup Final. (COMIC: Liberation of the Daleks)

Incarnations of the Doctor
By regenerating, the Doctor's personality and outer form changed greatly over time, though all of their incarnations were essentially the same person, retaining the memories, curiosity, eccentricity, and wisdom of the ones before.

By one account, the Doctor was the Timeless Child, and so they once had the ability to regenerate an indefinite number of times before their memory was redacted and their regenerations limited to the customary Time Lord limit of twelve. (TV: The Timeless Children)

Under their chosen name as "the Doctor", they regenerated fifteen times. Though the Doctor's first thirteen incarnations appeared male, (TV: The Day of the Doctor) at least three incarnations of the Doctor appeared to be women. (TV: The Woman Who Fell to Earth, PROSE: Rose, TV: Fugitive of the Judoon) In fact, Clive Finch's research revealed that some incarnations of the Doctor were also "in-between [male and female] or neither". (PROSE: Rose)

Despite appearances, the Eighth Doctor firmly denied ever having been a man or a woman, on two occasions, (PROSE: Interference - Book One, Beltempest) as did the Thirteenth Doctor. (PROSE: The Good Doctor)

With regards to the Timeless Child, even the Doctor had no idea how many lives had been lost, nor had any sense of their identities. (TV: Survivors of the Flux) Of those recorded, some of the Doctor's earliest known incarnations as the Timeless Child also presented as young women, including their first, second, third and sixth selves. (TV: The Timeless Children)

Each incarnation of the Doctor developed their own personal style, and differed in opinion and manner, but certain constants remained. For instance, though particular taste in fashion did change with each Doctor, one more-or-less constant within the Doctor's wardrobe was a coat or jacket, incorporated into an outfit, (TV: An Unearthly Child, The Power of the Daleks, Spearhead from Space, Castrovalva, The Twin Dilemma, Doctor Who, Rose, The Eleventh Hour, Deep Breath) or worn as an extra layer, like a trench coat. (TV: The Christmas Invasion, The Woman Who Fell to Earth) Several incarnations also had particular interest in hats, with special regards to their second, fourth and eleventh incarnations. (TV: The Power of the Daleks, Robot, The Big Bang, et al.)

The Doctor's known incarnations are described below:


 * The First Doctor was an unreadable, guarded figure who was, at first, slow to trust newcomers who learnt of him, but once his trust had been earned, he would show another side of himself as a staunch anti-authoritarian with a mischievous streak. This Doctor was often irascible. He made his anger obvious. He was protective of the young women he took on as companions; they reminded him of his granddaughter, Susan. This Doctor was a brilliant, often short-tempered scientist and keen strategist. He used his signet ring to help get himself through ordeals due to his physical age impeding him. He stole a TARDIS and took his granddaughter with him, joyriding through all space and time, without a clue as to how to pilot his Ship.


 * The Second Doctor, in contrast, was warm and wise. He was as surprised and frightened of alien menaces as those who faced them with him. He had a knack for manipulation and deception, and especially enjoyed to play a buffoon in order to trick his opponents into underestimating him so that he could better carry out his plans. His predecessor would refer to him as a "clown" due to his bumbling nature. He loved tootling on his recorder and carried around a 500-year diary, trying to record his travels, but ended up discarding it. He wore a big fur coat that dwarfed him, tying it closed with twine. A "cosmic hobo," he was forever getting himself in and out of trouble.


 * The Third Doctor was a more dashing figure than his predecessors. He was described by his first incarnation as a "dandy". (TV: The Three Doctors) He had a penchant for inventing gadgets and was skilled at martial arts, particularly Venusian aikido, and owned a vintage car named Bessie. His initially contentious relationship with Brigadier Lethbridge-Stewart softened into a close friendship during his exile on Earth, lasting through his future regenerations, despite not always agreeing with his actions. (TV: Doctor Who and the Silurians) He also displayed great affection for his female companions, particularly Jo Grant. He was a gallant action hero who was very protective of his companions.


 * The Fourth Doctor was more eccentric than his previous incarnations. Rarely without his long scarf, he carried jelly babies in his pockets, using them as bluffs, gifts and distractions—and occasionally snacks. He relied on his considerable charm, luck, and experience to get through bad situations. Although he retained his fondness for Earth, (TV: The Stones of Blood) he ended his regular association with UNIT almost immediately upon his regeneration and only occasionally returned to the planet. However, he had not properly resigned from the position. (TV: Pyramids of Mars) He hated to work and preferred travelling (TV: Robot) but liked history. He enjoyed the company of a wide range of individuals, such as Sarah Jane Smith, aide to his previous self, (TV: Robot) Leela, a savage, (TV: The Face of Evil) K9, a robot dog, (TV: The Invisible Enemy) and even a fellow Time Lord in Romana, though their relationship began poorly. (TV: The Ribos Operation)


 * The Fifth Doctor was fond of cricket and wore a stick of celery on his lapel that he used as a safety precaution for his allergy to certain gases in the praxis range of the spectrum. (TV: The Caves of Androzani) After a difficult regeneration, this Doctor displayed energy, compassion and innocence not seen in his predecessors. His character was very human and vulnerable. Like them, he used improvisation as the best way out of a tricky situation. The Fifth Doctor was the first incarnation since the First Doctor to go "hands-free" and forgo the usage of a sonic screwdriver after having it destroyed. He occasionally wore glasses, even though he didn't need them; he only wore them to make himself look clever. (TV: Time Crash) He was the first Doctor to sacrifice himself for another, when he and Peri Brown were dying from spectrox toxaemia; with only one dose of the antidote available, he gave her the cure rather than taking it himself.


 * The Sixth Doctor was a grandiose and eloquent incarnation. He sported a multi-coloured wardrobe that was often commented and sneered at, occasionally leading to him being mistaken for a jester. This Doctor loved a good quote, often making one he deemed appropriate during an adventure. He also proved to have great acting skills on numerous occasions. (TV: Mindwarp, The Ultimate Foe) His manic personality and acerbic wit could shade into moral passion, but his lack of concern for little things disgusted his companions. He was also capable of violent action, much more so than in past lives, and of killing without remorse when his life was threatened. (TV: The Two Doctors) Despite his bluster, he still could show great compassion and empathy. Like the Fourth Doctor, he spent most of his travels with a single companion.


 * The Seventh Doctor had a voice touched by a Scottish burr. A keen strategist and scientist and, especially early on in his life, lighthearted, this Doctor was a planner of the highest order. Embracing the complexities of time travel and his ability to manipulate and plan for the future, the Seventh Doctor fully embraced his role of Time's Champion, even if it risked alienating his companions. (TV: The Curse of Fenric) However, he wished to help heal psychological scars from which his companions suffered. (TV: The Greatest Show in the Galaxy, Ghost Light) It was at this point the Doctor began looking towards his own origins from the Dark Days of Gallifrey, realising he was far more than just another Time Lord. (TV: Remembrance of the Daleks, Silver Nemesis, PROSE: Lungbarrow)


 * The Eighth Doctor showed a romantic and sensitive side not displayed by previous Doctors. Less morally flexible than his immediate predecessor, the Eighth Doctor suffered from bouts of amnesia, first after his regeneration and again after Gallifrey was destroyed following the War in Heaven. (TV: Doctor Who, PROSE: The Ancestor Cell) He broke down after the death of his Great-Grandson Alex Campbell and companion Lucie Miller, who died defeating a Dalek invasion of Earth. (AUDIO: To the Death) Unlike other Doctors, the Eighth spent his travels crossing between parallel universes (AUDIO: Zagreus, PROSE: Time Zero) and amidst time paradoxes, making his personal timeline hard to piece together. (PROSE: Interference - Book One, Interference - Book Two, AUDIO: Storm Warning) He refused to take part in combat during the Last Great Time War, preferring instead to help those who were caught in the crossfire. (TV: The Night of the Doctor)


 * Looking at the Eighth Doctor's future, Marnal saw that the Doctor had three different ninth incarnations. (PROSE: The Gallifrey Chronicles)


 * The "War Doctor" was the disgraced ninth incarnation of the Doctor. He was an incarnation specifically chosen to be that of a warrior who would fight in the Last Great Time War. The regeneration into this incarnation was aided by the Sisterhood of Karn. (TV: The Night of the Doctor) Although being a warrior and showing anger if he was referred by his former name, he still showed charm and compassion like his earlier selves. Due to the belief that he had destroyed Gallifrey, he was treated with shame and contempt by his future incarnations. His eleventh incarnation stated that his actions broke "the promise" of the "name of the Doctor". (TV: The Name of the Doctor) This assessment changed somewhat once the real end of the Time War was revealed and was described after that as being the Doctor most of all by his future selves. (TV: The Day of the Doctor)


 * The Ninth Doctor considered himself the sole Time Lord survivor of the Time War (he spent his life thinking that he was responsible for destroying the Time Lords). He displayed much of the playfulness of his previous incarnations but was emotionally and psychologically scarred by the war and his role in it, which sometimes resulted in a detachment that was interpreted by some as cruelty. (TV: The End of the World, Dalek) When asked about his voice and accent, he responded, "Lots of planets have a North." (TV: Rose) He cared deeply for Rose Tyler; he began to heal thanks to her. (TV: Dalek, Journey's End) He also made dry jokes when facing danger or to diffuse tension. The Ninth Doctor ultimately sacrificed himself to save Rose's life, not only proving he cared deeply for her but allowing him to make peace with his past. (TV: The Parting of the Ways)


 * The Tenth Doctor had a manic personality with a fondness for human popular culture. However, his more outgoing personality traits largely existed to hide leftover emotional trauma from the Time War. While he had a bright, playful side, darker traits occasionally emerged. (TV: The Christmas Invasion, Tooth and Claw, School Reunion, The Runaway Bride) He continued his previous incarnation's care for Rose Tyler, even growing into platonic love. He was, however, unable or unwilling to express his exact feelings. (TV: Doomsday; Journey's End) He experienced other romances on occasion, including with historic figures Madame de Pompadour (TV: The Girl in the Fireplace) and Queen Elizabeth I. (TV: The End of Time, The Day of the Doctor) All these ended badly. He was the first Doctor to explicitly fear and dodge regeneration, since he had grown attached to his appearance and personality, and felt like it was a form of death and loss of identity. Indeed, he was the only Doctor to actually use up a regeneration to retain his form. (TV: Journey's End, The Time of the Doctor) When the time came for him to fully regenerate, he was completely heartbroken before accepting his destiny. (TV: The End of Time)


 * The Eleventh Doctor exhibited a renewed youthful enthusiasm for adventure. He could, however, quickly turn frantically angry and ruthless when circumstances demanded. (TV: The Eleventh Hour, The Beast Below, A Town Called Mercy) Like his second and seventh selves, his more playful side was often a front to obscure his true nature as a cunning schemer, often executing temporally complex plans and misdirections to achieve victory against his enemies. (TV: Day of the Moon, A Good Man Goes to War, The Wedding of River Song) He frequently referred to himself as being old, showing his age on more than a few occasions, (TV: Vincent and the Doctor, The Big Bang, The Impossible Astronaut, Closing Time) and often grappled with his ever growing mythical place in the universe. (TV: A Good Man Goes To War, The Wedding of River Song, The Name of the Doctor) Through his marriage to River Song, he found a sense of family again with her and his in-laws, and was distraught when circumstances separated him from them. (TV: The Power of Three, The Angels Take Manhattan, The Name of the Doctor) Some events still provided painful reminders of his role in the Time War. (TV: The Rings of Akhaten, The Time of the Doctor, et al.) He was the final incarnation before the Time Lords granted him a new regeneration cycle. (TV: The Time of the Doctor)


 * The Twelfth Doctor displayed an acerbic wit coupled with sarcasm. Like his seventh incarnation, he was initially manipulative and practical to a fault. He lacked much of the empathy present in his immediate predecessors, and as a result, found himself coming off as callous or uncaring on many occasions. He also shared the Eleventh Doctor's lack of tact and odd behaviour. Toward the start of his life, he had a tendency to brush off death around him, in order to focus on the task at hand. As a result, he expressed doubt as to whether he was a "good man". (TV: Into the Dalek) He eventually accepted that he wasn't a good man, but decided he wasn't a bad one either, being just "an idiot with a box". (TV: Death in Heaven) By the end of his life, the Twelfth Doctor sought "just [to] be kind". He fought for others, in the face of futility, because he felt it was right. (TV: The Doctor Falls) The Twelfth Doctor had an unwavering care for Clara Oswald, even when he felt she had betrayed him. (TV: Dark Water) When she eventually died, he "went too far" to get her back, and had to erase his memories of Clara. (TV: Hell Bent) He considered hope to be his major weakness, (TV: The Eaters of Light) and in the end, wanted nothing more than for to renounce her former ways and to stand with him, as his friend. (TV: World Enough and Time, The Doctor Falls)


 * The Thirteenth Doctor was curious, adaptable, and endlessly caring. Influenced by the words of her predecessor, this Doctor stood for kindness and compassion, willing to help anyone who needed it. She was a strong believer in hope, love, and the preservation of all life. (TV: Arachnids in the UK, The Witchfinders, Demons of the Punjab, The Battle of Ranskoor Av Kolos, et al.) She would encourage her companions, giving out points and gold stars, (TV: The Tsuranga Conundrum, Demons of the Punjab) and entrusting them with responsibilities. (TV: It Takes You Away, Resolution) Though early on her TARDIS crew had a "very flat team structure", (TV: The Witchfinders) later in her life the Thirteenth Doctor became more secretive, withholding information from her companions while she worked on processing things alone, and expecting them to follow her commands. (TV: Revolution of the Daleks, The Halloween Apocalypse, Once, Upon Time) A series of events which led the Doctor to question her own past, and saw Gallifrey destroyed, (TV: Spyfall, Fugitive of the Judoon, The Timeless Children) made her feel less confident in her identity, and far less hopeful, (TV: The Timeless Children, Revolution of the Daleks) lending a much more frustrated and acerbic edge to her interactions with Team TARDIS, often berating them for their comments and actions. (TV: Fugitive of the Judoon, The Haunting of Villa Diodati, Ascension of the Cybermen) She resolved some of those doubts, coming to realise she was still the Doctor, the woman she had chosen to become, (TV: Revolution of the Daleks) but remained a guarded figure, keeping her deepest questions from her closest friends, and trying to solve everything on her own, while failing to communicate what worried her the most. (TV: The Halloween Apocalypse, Once, Upon Time) Lost in the midst of new revelations, she was angry with Tecteun for having taken away the life she might have lived, (TV: Survivors of the Flux) and was willing to sacrifice everything she had to get some answers. (TV: Once, Upon Time)


 * was a short-lived incarnation of the Doctor after he used stolen Time Lord technology to make the Thirteenth Doctor undergo a forced regeneration, transferring his mind into the Doctor's body as she regenerated to become physically identical to him. Intent on ruining the Doctor's reputation, the Master's plans were cut short when Yasmin Khan and Vinder forced him to reverse the regeneration and restore the Thirteenth Doctor, returning the Master to his own body. (TV: The Power of the Doctor)


 * The Fourteenth Doctor was shocked that he looked identical to their tenth incarnation. (TV: The Power of the Doctor)

Ambiguous incarnations
A number of other incarnations have been chronicled; however, where they fall within the Doctor's lifetime is unclear:


 * The Other was the mythological third founding father of Gallifrey, several accounts link the Doctor to the Other, in some the Doctor is the Other reincarnated through the Loom of the House of Lungbarrow, while other accounts depict the Other as the Doctor from some point in the Future. (PROSE: Remembrance of the Daleks, Lungbarrow, The Scrolls of Rassilon, et al.)
 * Eight unknown Doctors seen in a mindbending contest between the Fourth Doctor and Morbius. (TV: The Brain of Morbius) It was later revealed by the Master that these were incarnations from before the First Doctor, the memory of which had been redacted from the Doctor's mind. (TV: The Timeless Children)
 * The Fugitive Doctor was an incarnation of the Doctor who worked for the Division. She participated in the Siege of Atropos, bringing an end to the Dark Times by securing victory for the Time Lords in the Founding Conflict. Though the Thirteenth Doctor was certain this incarnation belonged to her past, (TV: Once, Upon Time) the Fugitive Doctor herself, as a Matrix projection, was elusive about her exact placement in the Doctor's timeline. (TV: The Timeless Children) She escaped service, no longer willing to play a part in the Division's plans, and hid on Earth under a Chameleon Arch, as Ruth Clayton. Later, she returned to her travels. (TV: Fugitive of the Judoon, PROSE: The Tourist)
 * The Watcher was a manifestation of the Doctor during his fourth regeneration. He went back in time to the Fourth Doctor's final adventure and ensured the events leading to his death would still happen. When the Doctor finally regenerated, he merged with the Watcher to briefly become him, after which he emerged from the regeneration as the Fifth Doctor. (TV: Logopolis)
 * The Valeyard was, according to the Master, an amalgamation of the darker sides of the Doctor's nature, somewhere between the Doctor's twelfth and final incarnation. He shared the characteristics and dress sense of the Master. He sought to take the Sixth Doctor's seven remaining regenerations and have them for himself. (TV: The Ultimate Foe) He was finally defeated in Victorian era London. (PROSE: Matrix) The Great Intelligence (TV: The Name of the Doctor) and the Testimony were aware of the Valeyard's existence. (TV: Twice Upon a Time)
 * One incarnation travelled to an alternate world and taught King Arthur. He became known as Merlin. (PROSE: Battlefield, TV: Battlefield) He was also temporarily exiled to Antýkhon, where he was known as "Muldwych" and was visited by the Seventh Doctor. (PROSE: Birthright) He was good friends with Irving Braxiatel. (PROSE: The Collection)
 * One incarnation existed somepoint after the life of the Seventh Doctor, telling his former self that Gallifrey had not repealed the First Law of Time by his life. (COMIC: Party Animals) However, after the planet was destroyed, this incarnation gave up his status as being (PROSE: Cyber-Hunt) an incarnation of the Doctor (COMIC: Party Animals) so that a man in black could restore his lost homeworld. With new, different versions (PROSE: Cyber-Hunt) of the Doctor (TV: The Day of the Doctor, et. al) taking the place he could have held, the man took on the name "Fred". (PROSE: Cyber-Hunt)
 * Clive Finch had photographs of a tall, black female Doctor who used a flaming sword and a young Doctor of indeterminate gender in a hi-tech wheelchair. (PROSE: Rose)
 * A Doctor was working on behalf of the Time Lords. He was described as having a "harsh, angular face" and "thumb-tucked arrogance". (PROSE: From Eternity)
 * After his previous incarnation was killed by Mestizer, one Doctor stayed in 1949 London for a while, where he was tracked by Honoré Lechasseur. (PROSE: The Cabinet of Light)
 * The Emperor, who resembled a short-haired version of the Eighth Doctor, (PROSE: The Gallifrey Chronicles) ruled the end of the universe from the Needle. He was one of the four surviving elementals. According to the Klade, the Emperor was a ruthless and fearsome individual. Shortly after the birth of his daughter Miranda Dawkins, the Emperor was assassinated. (PROSE: Father Time)
 * The Doctor's last incarnation within the version of history that contained the War in Heaven both faked his death on Dronid during the first battle of the War and eventually actually died, with his corpse being planted there. However, the timelines changed when the Eighth Doctor learned of his future self's death and the existence of this Doctor's corpse became a paradox. (PROSE: Alien Bodies)
 * The Curator was a future incarnation of the Doctor, (COMIC: The Then and the Now) who had many forms. (AUDIO: Crossed Lines) The Curator claimed he "revisited" the "old favourites" among his past faces. (TV: The Day of the Doctor) In his encounters with Liv Chenka and Helen Sinclair and the Eleventh Doctor he resembled an older version of the Fourth Doctor, (TV: The Day of the Doctor, AUDIO: Lost Property) Tania Bell once met him in the form of an elder Eleventh Doctor, (AUDIO: The Keys of Baker Street) and whilst resolving alternate timelines he took a more proactive form resembling an older Sixth Doctor. (AUDIO: Crossed Lines) "Partially retired", the Curator fulfilled the function of Curator of the Under Gallery, which had been awarded to the Doctor by his one-time wife Elizabeth I. He also revisited old friends such as Brigadier Lethbridge-Stewart and also occupied himself by editing scattered writings of his past incarnations, the "Doctor Papers", into a coherent history of the Last Great Time War. (PROSE: The Day of the Doctor)
 * A powerful cosmic being called the Father of Time, or simply Time, who was known as a legend to the First Doctor, was eventually understood by him to actually be his own distant future self. (COMIC: The Test of Time)
 * According to the stories that Novice Hame had heard by the end of her life, the Doctor had "hundreds of faces and forms", including not only men and women but also animals. (WC: The Secret of Novice Hame)

Ambiguous individuals
Beyond the incarnations who existed at unclear parts of the Doctor's timeline, there existed other individuals across the universe and beyond who met the Doctor's description, attitude, or actions.


 * A time traveller known as "the Gestalt" traveled in a blue, rectangular timeship. (PROSE: Ring Theory)
 * Grandfather Halfling was a half-human half-Homeworlder who lived in the City of the Saved after the end of the universe. (PROSE: The Book of the War) At times, the Eighth Doctor stated he was half-human. (TV: Doctor Who, et. al) Halfling was also believed to travel out of the City often (PROSE: The Book of the War) and was known to have met V. M. McCrimmon before her resurrection into the City. (PROSE: Postscript) When the Twelfth Doctor regenerated into the Thirteenth Doctor, (TV: Twice Upon a Time) her "actualised potential" sent a postcard to the City to be read by Halfling and McCrimmon, with it being clear that Halfling and the blonde woman in the postcard shared a connection. (PROSE: Postscript)

Adventures by unknown incarnations of the Doctor
Due to the Doctor's many adventures it was sometimes unclear as to which incarnation of the Doctor experienced them. Some of these adventures include:
 * An incarnation of the Doctor after his sixth one visited Peri Brown on Krontep. (PROSE: Reunion)
 * Luj had met an incarnation of the Doctor prior to the Seventh. He was male like the Seventh Doctor, with Luj later being surprised to learn that regeneration could cause a change in gender and sex. (COMIC: Who's That Girl!)
 * A Doctor once saved a young girl from a monster living in her barn. This incarnation bears similarity to the Sixth Doctor. (PROSE: The Colour of Monsters)
 * A Doctor was once trapped on a Dalek-occupied planet. (PROSE: The Dalek Factor) He used the name Professor suggesting the Seventh Doctor or later. (TV: Dragonfire et al.)
 * A Doctor failed to prevent the Master from escaping. He tried to take off after him, but the Master had sabotaged the Doctor's TARDIS, forcing him to play a quiz game before he could start the engines again, and thus successfully delaying him. (PROSE: Enjoy the Game)
 * Whilst traveling with Rose Tyler, the Tenth Doctor disclosed that he had earlier encountered Krillitanes who appeared as humanoids distinguished by their "really long necks". (TV: School Reunion)
 * A Doctor spoke to Jack Harkness of Silurian mythology, Huon particles, and Racnoss energy, leading him to speculate that an expansion of their hibernation matrix resulted in the Blessing. (TV: The Blood Line) Jack was a companion of the Ninth and Tenth Doctors. (TV: Utopia)
 * A Doctor once met Vastra, Jenny and Strax at the Tower of London in 1897. (COMIC: The Giant's Heart)
 * A Doctor fought Mestizer after regenerating in London, 1949. (PROSE: The Cabinet of Light) He later battled the Sodality. (PROSE: Child of Time)
 * The Thirteenth Doctor, soon after regenerating, recalled once having spent three weeks as a hologram. (TV: The Ghost Monument)
 * The Thirteenth Doctor later recalled once having lived in the Australian outback for 123 years. (TV: Spyfall)

Overview
Due to the unique structure of their biology, the Doctor had the ability to regenerate, to "cheat death". (TV: The Parting of the Ways) A Time Lord was usually limited to twelve regenerations. (TV: The Deadly Assassin, Mawdryn Undead, Doctor Who, The Time of the Doctor) The High Council of the Time Lords could influence regenerations, treating them as punishment (TV: The War Games) and reward. (TV: The Five Doctors, Utopia, The Time of the Doctor) At times, enemies coveted the Doctor's future regenerations and tried to take them for their own. (TV: Mawdryn Undead, Doctor Who, Human Nature/The Family of Blood, The Witch's Familiar)

The effect of regeneration on the Doctor in the time immediately following the event varied from incarnation to incarnation. In some cases, the Doctor regained their faculties quickly, erratic behaviour notwithstanding. (TV: The Power of the Daleks, The Twin Dilemma, The Eleventh Hour) On one occasion when the regenerative process was postponed for a long time, he was rendered amnesiac. (TV: Doctor Who) In most cases, the Doctor was incapacitated for a period of time before ultimately recovering. (TV: Spearhead from Space, Robot, Castrovalva, Time and the Rani, The Christmas Invasion) There were also rare cases where the Doctor was able to delay regeneration from setting in for an extended period of time. The Tenth Doctor once did such to visit all of his past companions - though, after the long delay, the resulting energy release was catastrophic for the TARDIS. (TV: The End of Time, Death of the Doctor)

After gaining a new regenerative cycle, the Twelfth Doctor did something similar while trying to decide whether or not to regenerate. He called this period "a state of grace" where the Time Lord within the state would be briefly restored to health before weakening and must choose to either regenerate or die. Like the Tenth Doctor, the Twelfth Doctor's regeneration was highly explosive as a result. (TV: Twice Upon a Time) In contrast, the First Doctor's regeneration into the Second Doctor, despite having delayed his regeneration like the Tenth and Twelfth Doctors, was not explosive at all. (TV: The Tenth Planet) However, the Twelfth Doctor did delay the change further after the First Doctor left, (TV: Twice Upon a Time) and the Tenth Doctor delayed it longer than the Twelfth, having managed to visit every single one of his previous companions before changing. (TV: Death of the Doctor)

Due to the regeneration into the War Doctor and the Tenth Doctor's aborted regeneration, the Eleventh Doctor was actually the Doctor's last incarnation until the Time Lords gifted him with a new regenerative cycle at the end of that life. (TV: The Time of the Doctor) It was unclear exactly how many regenerations he was given, the Twelfth Doctor stated that he himself was not sure and didn't rule out the possibility that his new cycle could be infinite as he stated he could now possibly regenerate forever. (TV: Kill the Moon) Indeed, Rassilon, while threatening the Twelfth Doctor with his gauntlet, remarked to him "how many regenerations did we grant you? I've got all night," (TV: Hell Bent) and when all of the incarnations, past and future, of the Doctor teamed up to help preserve Gallifrey from disaster as it slipped into a parallel pocket universe at the end of the Last Great Time War, there were enough of them that the sky was filled with "a blizzard of blue boxes". (PROSE: The Day of the Doctor)

The Twelfth Doctor also reflected that, over his lives, his regenerations had grown more destructive and volcanic; as he warned the First Doctor, the Eleventh Doctor's regeneration into him was powerful enough to wipe out an entire Dalek Fleet. (PROSE: Twice Upon a Time) The Thirteenth Doctor later learned that she was originally the Timeless Child, a being from another unknown universe or dimension with the ability to regenerate an indefinite number of times. Along with the Doctor's memories of their lives prior to the First Doctor being redacted, the Doctor's ability to regenerate appeared to have been reduced to that of a normal Time Lord (TV: The Timeless Children) which meant the Eleventh Doctor had to receive a second regeneration cycle from the Time Lords in order to continue living. (TV: The Time of the Doctor)

The Doctor would later regenerate into another new incarnation while alone in the TARDIS. (PROSE: Contents)

Causes of regeneration

 * The First Doctor was weakened by Mondas as it drained Earth's energy, succumbing to old age. (TV: The Tenth Planet) He hesitated for a time to regenerate, fearing the change, entering "a state of grace" where he was briefly restored to health before he had to make a choice. Following an adventure with the Twelfth Doctor, the First Doctor chose to regenerate after seeing the man he would ultimately become. (TV: Twice Upon a Time)


 * The Second Doctor had regeneration forced upon him by the Time Lords as part of his punishment for breaking the Laws of Time; his appearance was chosen for him after he rejected all choices. (TV: The War Games) Before he could change, however, he was picked out by the Celestial Intervention Agency to be their "hired gun" (PROSE: World Game) and perform tasks. When he was done, he tried to run away, but eventually got caught and forced into regenerating. (COMIC: The Night Walkers)


 * The Third Doctor suffered radiation poisoning from the Great One's web of Metebelis crystals, then got lost in the Time Vortex for a decade before returning to UNIT HQ. (TV: Planet of the Spiders, PROSE: Love and War)


 * The Fourth Doctor was severely injured after plummeting from the Pharos Project radio telescope. (TV: Logopolis)


 * The Fifth Doctor suffered exposure to unrefined Spectrox, sacrificing himself to give the bat's milk needed to cure it to Peri. (TV: The Caves of Androzani)


 * The Sixth Doctor was compelled to travel to the Lakertyan System by a mental impulse sent to him by an alternative future Sixth Doctor, in order to stop the Valeyard from stealing the lives of every Time Lord to ever exist. Upon arrival, his TARDIS was bombarded by radiation coming from Lakertya, radiation that was deadly to Time Lords. He died from exposure to said radiation. (AUDIO: The Brink of Death)


 * The Seventh Doctor was lightly injured after being caught in the middle of a gang war; his circulatory system was damaged by Grace Holloway during surgery to "fix" his abnormal heartbeat. (TV: Doctor Who)


 * The Eighth Doctor regenerated after he tried to help a pilot named Cass Fermazzi escape from a crashing ship. Cass refused his help however when she identified his ship as a TARDIS and therefore his being a Time Lord, who she despised because of the Time War. He died when the ship crashed but was revived temporarily by the Sisterhood of Karn, who not only offered to trigger his regeneration, they also offered him a choice on the characteristics of his next incarnation. (TV: The Night of the Doctor)


 * The "War Doctor" regenerated because his long-lived elderly body had grown precariously weak after spending an entire lifetime fighting in the Time War. The tipping point was at the end of the war when he helped to save Gallifrey from being destroyed by one billion-billion Daleks and place it in a different dimension. With the Time War concluded and his will to persist as that incarnation for as long it waged settled, his regeneration began before his vitality drained entirely. He remarked that his body was "wearing a bit thin," like his distant predecessor. (TV: The Day of the Doctor)


 * The Ninth Doctor removed the Time Vortex's energy from Rose Tyler, channelling it back into the heart of the TARDIS. However, his brief possession of the energy very nearly destroyed his cellular structure completely. Because of the damage, he had to regenerate. (TV: The Parting of the Ways)


 * The Tenth Doctor was grazed by a shot fired from a Dalek's gunstick during their 2009 invasion of Earth. He used his regeneration energy to heal himself, but then syphoned off the rest of the regeneration into his extra hand to prevent transformation into another form. The regeneration energy stored in the hand allowed it to grow into another Doctor, when it came into contact with Donna Noble. (TV: The Stolen Earth/Journey's End)


 * The Tenth Doctor regenerated truly by absorbing the radiation from a nuclear vault supply to spare Wilfred Mott. Unlike most of his predecessors, he held off the regeneration for a long time; the result was explosive damage to the TARDIS when he finally completed the process, that caused it to crash and regenerate itself. (TV: The End of Time)


 * The Eleventh Doctor spent centuries defending the town of Christmas, on the planet Trenzalore. Before his body succumbed to old age, the Time Lords granted him a new regeneration cycle, prompting a thirteenth regeneration. His most destructive regeneration process yet, he destroyed several Daleks and their ship with the regeneration energy and restored his body to a younger form but did not immediately change him into his next incarnation. The change finally occurred shortly after he returned to the TARDIS. (TV: The Time of the Doctor)


 * The Twelfth Doctor was struck several times by Cyberman energy beams during the Battle of Floor 0507, requiring him to regenerate. (TV: The Doctor Falls) Upon awakening in the TARDIS, the Doctor again started to regenerate, but held it back, entering "a state of grace" during which he went on a final adventure with the First Doctor. After the adventure, the Twelfth Doctor regenerated explosively, severely damaging the TARDIS. (TV: Twice Upon a Time)


 * The Thirteenth Doctor was mortally wounded by using his Tissue Compression Eliminator to direct the Qurunx's destructive blast at her. After saying goodbye to Yasmin Khan, she underwent a solitary regeneration on a cliffside which, unlike the Doctor's previous regenerations, was fairly peaceful. However, it was unusual in that the Doctor's clothes were changed by the regeneration as well and they regenerated into an incarnation that was physically identical to the Tenth Doctor. (TV: The Power of the Doctor)

Points of view on past incarnations
An interesting aspect of the Doctor's personality was that they occasionally expressed a personal liking or disliking for particular incarnations, though this opinion depended on the incarnation making the assessment. The Doctor's tenth incarnation expressed a deep fondness for his fifth incarnation, (TV: Time Crash) and slight disdain for his ninth, considering him unnecessarily violent. (TV: Journey's End) The Twelfth Doctor was obviously flattered when he believed, incorrectly, that his companion was romantically involved with a fellow teacher he considered to bear a resemblance to his eleventh incarnation. (TV: The Caretaker) The Fifth Doctor was disliked by his immediate successor. (TV: The Twin Dilemma)

In another instance, the Fourth Doctor made reference to the Third Doctor, saying, "Some people liked it, but I prefer this one." (TV: The Brain of Morbius) The Twelfth Doctor told his first incarnation that "there [were] a few false starts [before becoming him], but you get there in the end". (TV: Twice Upon a Time) The Seventh Doctor was also annoyed when he had to work with the Fifth Doctor, seeing him as "not even one of the good ones". The Fifth Doctor was equally disgusted by what he would become. (PROSE: Cold Fusion) The Fifth Doctor also stated after meeting his past selves that he was not the man he had been - and "thank goodness for that!". (TV: The Five Doctors) Immediately before his regeneration, the Tenth Doctor stated, "I don't want to go", showing he had become attached to his current self. Immediately after his twelfth regeneration, the Eleventh Doctor remarked upon his new nose, stating that, "I've had worse" — possibly a reference to multiple incarnations, including his third, who was once described as a "long-shanked fellow with a mighty nose". (TV: The End of Time, The Time Warrior) The Eleventh Doctor also at one point expressed loathing for his first incarnation's initial personality, considering himself at that time a foolish and arrogant liar and a selfish coward. (COMIC: Hunters of the Burning Stone)

Before learning the true outcome of the Time War, the Eleventh Doctor expressed an even greater hate for the "War Doctor" whose actions were so shameful that he went against "the name of the Doctor" and not counting him among his incarnations. (TV: The Name of the Doctor) Both the Tenth and Eleventh Doctors however forgave their war incarnation and honoured him as being the Doctor more than any of his incarnations once they learnt the real result of the Time War. (TV: The Day of the Doctor)

Willingness to change
The First Doctor, even as his ailing body began the regenerative process, tried to hold back the change, maintaining that he had "the courage and the right to live and die as [him]self." However, he confided to the Twelfth Doctor that he was motivated by fear, being "very, very afraid." After learning who he would become and witnessing his future self save Archibald Hamish Lethbridge-Stewart, the Doctor decided that he was ready and so completed his first regeneration. (TV: Twice Upon a Time, The Tenth Planet)

The Second Doctor's view on the prospect of changing was influenced by the fact that it was the Time Lords who forced him to do so, protesting that they could not do so without consulting him. Though he was provided with a selection of faces from which to choose from, the Doctor rejected all of them, which he attributed to being "very particular". (TV: The War Games, COMIC: The Night Walkers)

After confronting the Great One, the dying Third Doctor explained to Sarah Jane Smith that facing his fear was more important than "just going on living", only managing to regenerate with the assistance of K'anpo Rimpoche. (TV: Planet of the Spiders) Earlier, he was unfazed to know that he would regenerate. (TV: The Five Doctors)

Gravely wounded after falling from the Pharos Project telescope, the Fourth Doctor was content to regenerate, assuring his present companions that it was "the end, but the moment has been prepared for" before he merged with the Watcher to regenerate into the Fifth Doctor. (TV: Logopolis)

When both he and Peri Brown contracted the lethal spectrox toxaemia, the Fifth Doctor, left with only enough of the queen bat's milk to cure one of them, selflessly used it to cure Peri, unsure as to whether the affliction would even allow him to regenerate. Nevertheless, he entered and completed the regenerative process, with his former companions urging him not to die. (TV: The Caves of Androzani)

Having been exposed to radiation deadly to Time Lords, the Sixth Doctor believed that he was to finally die until he heard the voice of the Seventh Doctor. Feeling the change coming, the dying Doctor was assured that he would indeed regenerate, confident that his future was "in safe hands". (AUDIO: The Brink of Death)

After spending some time avoiding getting involved in the Last Great Time War, the dying Eighth Doctor requested that the Sisterhood of Karn make him a warrior, with Ohila providing a potion for him to drink before he regenerated into the War Doctor. (TV: The Night of the Doctor) She would later claim that the drink she gave him was just lemonade and dry ice, and her "moment of theatre" was simply an act to trick him into regenerating. (PROSE: Twice Upon a Time)

Feeling the regenerative process start as his body was "wearing a bit thin", the War Doctor, having just saved Gallifrey, was content as he regenerated into the Ninth Doctor. (TV: The Day of the Doctor) Likewise, the Ninth Doctor felt the same as his regeneration neared, taking the time to joke about what he may become and assuring both Rose Tyler and himself that they were "fantastic". (TV: The Parting of the Ways)

In contrast, the Tenth Doctor hesitated to change. Mortally wounded by a Dalek during the 21st century Dalek invasion of Earth, (TV: The Stolen Earth) the Doctor regenerated to heal himself but used his severed hand to siphon of the rest of his regeneration energy before he could change, rhetorically asking Rose why would he want to do so, he added "look at me". (TV: Journey's End) Nevertheless, this still counted as the Doctor's eleventh regeneration, and the Eleventh Doctor would attribute this instance of regenerating but keeping the same face to "vanity issues". (TV: The Time of the Doctor)

Later, the Doctor became aware of his impending death after seeing Ood Sigma (TV: The Waters of Mars) and so moved to avoid it by traveling. He confided to Wilfred Mott that even to regenerate would feel like dying, that he would be dead while "some new man [went] sauntering away". Ultimately, the prophecy was fulfilled when Wilf knocked four times from a locked booth which was to be flooded with radiation. Distraught, the Doctor bemoaned his fate while Wilf told him to go, noting that he was an old man who had his time. Agreeing with Wilf's assessment, the Doctor raged that the human was "not remotely important" whereas he "could do so much more". Ultimately, the Doctor still absorbed the radiation in Wilf's stead, sustaining fatal damage. After spending some time looking back on all his old companions, (TV: Death of the Doctor) the Doctor's injury caught up with him and he returned to the TARDIS where, in tears, he gave his last words "I don't want to go." before regenerating. (TV; The End of Time) In an alternative timeline envisioned by a continuity bomb, instead of sacrificing himself, the Doctor let Wilfred die in the radiation chamber of the Immortality Gate, viewing himself to be "more valuable to the universe", though he regretted his choice and broke down in tears immediately afterwards. (COMIC: Four Doctors)

The Eleventh Doctor did not share the outlook of his predecessor, though it should be noted that for the majority of life he believed that he was the "last Doctor", having expended all his regenerations. (AUDIO: Regeneration Impossible) Finding himself speak briefly with the voice of the Tenth Doctor, the Doctor's Ganger cried out "No, let it go, we've moved on!" (TV: The Almost People) Hearing the Tenth Doctor comment that he did not want to go to Trenzalore, where the Doctor was said to have died, the Eleventh Doctor made light of his last words when he told Clara Oswald that "he always [said] that." (TV: The Day of the Doctor) At the end of his life on Trenzalore, the Doctor was enabled to regenerate again after being provided with additional regeneration energy "love from Gallifrey". After making a phone call to a near future version of Clara, convincing her to stay and help the newly regenerated Twelfth Doctor, (TV: Deep Breath) the Eleventh Doctor was content to change as he spoke to the present Clara: "We all change, when you think about it. We're all different people all through our lives. And that's okay, that's good, you've got to keep moving, so long as you remember all the people that you used to be. I will not forget one line of this. Not one day. I swear. I will always remember when the Doctor was me."

- The Eleventh Doctor.

After being mortally wounded in the Battle of Floor 0507, the Twelfth Doctor held back his regeneration, having grown tired of "being somebody else". (TV: The Doctor Falls) Even after being brought into contact with the similarly-minded First Doctor, whose hesitance to chance took him by surprise, the Twelfth Doctor was still prepared to die until he was challenged by the glass avatar of his former companion, Bill Potts. Realising that everybody was "important to somebody, somewhere", the Doctor, after saving the life of Lethbridge-Stewart, returned to his TARDIS where, acknowledging that the universe still needed saving, he conceded that one more lifetime "wouldn't kill anyone", "well, except me." After addressing his forthcoming incarnation, the Doctor gave his last words "Doctor, I let you go." before finally regenerating. (TV: Twice Upon a Time)

Though she longed for more time, the Thirteenth Doctor was more accepting of the coming change, holding the process back only to have a final trip with Yaz. Wishing that she could see what happened next, in her final words she told the next Doctor "tag, you're it". (TV: The Power of the Doctor)

Impacting future incarnations
The Doctor on occasion performed acts that were expected to have an impact on future incarnations. Once, in order to recharge the TARDIS, the Tenth Doctor transferred some of his life energy, an act he acknowledged shortened his lifespan (and, by extension, the life of his ultimate final incarnation) by ten years. (TV: Rise of the Cybermen) Later, the Twelfth Doctor gave up some of his regeneration energy to revive Davros, (TV: The Witch's Familiar) as did the Eleventh Doctor to heal River Song's wrist; (TV: The Angels Take Manhattan) when River Song did something similar to save the Eleventh Doctor's life, it was stated that doing so cost her ability to regenerate. (TV: Let's Kill Hitler) Indeed, River pointed out to the Eleventh Doctor that he had wasted regeneration energy. (TV: The Angels Take Manhattan)

The Twelfth Doctor, after becoming blind, once created a device capable of borrowing eyesight from a future version of his current incarnation, but at the possible cost of being permanently blinded or having all possibility of future regeneration disabled; however, this took place in a computer-generated simulation. (TV: Extremis)

Abilities
Beyond their capacity to regenerate, the Doctor had many abilities, all of which came in handy at one point or another, when faced with unforeseen challenges. In almost all circumstances, the Doctor was adept at analysing, assessing and quickly responding when new dangers arose. This included understanding the balance of power, and weighing up different options which might tip this balance in their favour. (TV: Once, Upon Time) "I spend my life walking into new places and weighing things up fast. Who's who? Who has the power? Who's in danger? How fast danger is coming. Also, how likely my friends are to die. I've got good at figuring all of that out at speed."

- Thirteenth Doctor

Even before they took on the name "the Doctor", they "always were fast at processing everything". (TV: Survivors of the Flux) They were also quick to deduce their whereabouts, so long as they had something to anchor a hypothesis. By smell alone, the Tenth Doctor could identify the 1920s. (TV: The Unicorn and the Wasp) They could also smell out paradoxes. (COMIC: Defender of the Daleks) The Doctor was a master manipulator, strategist, and trickster in all their incarnations, able to devise and improvise many schemes to defeat adversaries or spin impossible situations to their advantage and achieve victory. (TV: The Three Doctors, Remembrance of the Daleks, A Good Man Goes to War, The Time of the Doctor)

Time Lord abilities
As a Time Lord, the Doctor had a respiratory bypass system, which allowed them to hold their breath for an extended period of time, in order to survive strangulation or (TV: Spearhead from Space, Pyramids of Mars) suffocation, (TV: The Caves of Androzani, Smith and Jones) and to avoid drowning. (TV: The Witchfinders)

Even in the vacuum of space, the Doctor could survive far longer than a human, (TV: Four to Doomsday, Oxygen) though this left the Twelfth Doctor blinded. (TV: Oxygen)

The Doctor also had a binary vascular system, with two hearts. (TV: Spearhead from Space) This meant that many attempts to kill them by stopping their heart were unsuccessful. Though the Doctor had trouble with just one heart, their second heart could be resuscitated again, to restore full health, so long as one heartbeat remained. (TV: The Shakespeare Code, The Power of Three)

Knowledge
The Doctor is highly intelligent throughout their incarnations, with the Thirteenth Doctor once claiming to have an understanding of "pretty much everything". (COMIC: A New Beginning) The Second Doctor successfully convinced an Ice Warrior to spare his life by claiming to be a genius. (TV: The Seeds of Death) The Tenth Doctor told John Lumic that he would call him a genius "except I'm in the room", (TV: The Age of Steel) and told Professor Yana on Malcassairo that he didn't have many chances to say this to others. (TV: Utopia)

Cassandra O'Brien.Δ17 had reason to believe the Ninth Doctor was the "school swot". (TV: The End of the World) This same Doctor was also described by the Editor to have infinite knowledge. (TV: The Long Game) While recalling an incident in which he escaped death at the hands of Android Assassins, described the Doctor as a swot. (TV: The Witch's Familiar)

The Abzorbaloff valued the Tenth Doctor's experience and knowledge, and sought to absorb him to acquire it. (TV: Love & Monsters) The Eleventh Doctor once declared that he knew many things about the universe from living a long life, including secrets that must never be told and knowledge that must never be spoken. (TV: The Rings of Akhaten)

Languages
The Ninth Doctor claimed he could speak five billion languages. (TV: The Parting of the Ways) The Doctor's native language was probably Modern Gallifreyan, but they seemed to prefer speaking English, (TV: The Mind Robber) always with an accent that was similar to accents used in the British Isles. (TV: An Unearthly Child, The Power of the Daleks, Spearhead from Space, Robot, Castrovalva) This accent changed from incarnation to incarnation. For example, both the Seventh (TV: Time and the Rani) and the Twelfth Doctor (TV: The Time of the Doctor) spoke with an accent similar to one used in Scotland. Rose Tyler noted the accent of the Ninth Doctor made him sound like he came from "the north", (TV: Rose) while Harriet Jones described it as "a northern accent", (TV: World War Three) both of them referring to the north of England. The Doctor once retorted to Rose that "lots of planets have a north". (TV: Rose) American Grace Holloway once told a San Franciscan policeman that the Eighth Doctor was "British". (TV: Doctor Who)

The Doctor could read and write Old High Gallifreyan, (TV: The Time of Angels) a skill unusual even among Time Lords. (TV: The Five Doctors) They also spoke the language of the Judoon, (TV: The Stolen Earth) Delphon (a language "spoken" using only eyebrow movements), (TV: Spearhead from Space) several Chinese languages, (TV: The Mind of Evil, The Talons of Weng-Chiang) Ancient North Martian, (TV: The Waters of Mars) Venusian, (TV: The Curse of Peladon) Vietnamese, (PROSE: Interesting Times) Portuguese (TV: Black Orchid) and Tritovore. (TV: Planet of the Dead) They knew at least some Sycoraxic (TV: The Christmas Invasion) and a language of Tiaanamat, which sounded like canine barking to human ears. (TV: The Rings of Akhaten) The Second Doctor did not seem to understand French, (TV: The War Games) but later became fluent in it across several periods of French history. (TV: The Girl in the Fireplace) They also claimed to speak "sabre-toothed tiger", (PROSE: Sick Building) "baby", (TV: A Good Man Goes to War, Closing Time) "cat", (TV: The Lodger) "horse" (TV: A Town Called Mercy) and "dinosaur". (TV: Deep Breath) The Eleventh Doctor claimed that he "spoke everything". (TV: A Good Man Goes to War, Closing Time) The Doctor once understood British Sign Language; by their twelfth incarnation, though, they had lost the skill, saying that it had been "deleted" and replaced with semaphore. (TV: Under the Lake) The Tenth Doctor claimed to never have learnt to speak Welsh, but did carry a pocket Gallifreyan-Cymraeg phrasebook on at least one occasion when he visited Arcopolis. (PROSE: The Eyeless)

Other realities
Rose Tyler believed that the Doctor was a "one-off" across the multiverse, (AUDIO: The Last Party of Earth) due to the fact that she could find no trace of them in several parallel universes she had visited. (AUDIO: The Endless Night, The Flood, Ghost Machines) However, other accounts showed the Doctor did have many counterparts in other universes across the multiverse or even omniverse. (COMIC: The Glorious Dead, PROSE: Spiral Scratch, AUDIO: The Library in the Body) The Seventh Doctor's companion Ace once speculated that his parallel selves were the closest thing the Doctor had to a family. (COMIC: Final Genesis)

Additionally, the Doctor's time stream was constantly shifting, alongside the palimpsest universe among them; this meant that even the "prime" Doctor's time-stream encompassed many alternative versions of their history, whom they could sometimes remember. (PROSE: The Infinity Doctors, Unnatural History)

Alternative timelines
In his observations of the universe's past and future changing, Omega claimed to have seen an infinite number of Doctors.

In an altered state of reality, the Doctor, who resembled a short-haired version of the Eighth Doctor, returned to living on Gallifrey where he married and taught at the Academy. Years after his wife died, this Doctor organised a peace conference to resolve the Rutan-Sontaran War, during which the Effect was discovered by the Time Lords. Investigating the Effect led this Doctor to encounter Omega and he subsequently thwarted his attempt to escape the anti-matter universe and seize the Eye of Harmony's singularity. Afterwards the Doctor resolved to leave Gallifrey. During these events the Doctor experienced a vision (PROSE: The Infinity Doctors) which was somehow shared by the Eighth Doctor. (PROSE: Father Time)

In an alternate timeline visited by Siblings Same and Different the Doctor's TARDIS was possessed by a malevolent hunger, forcing the Doctor to rally an army to hunt and destroy the TARDIS. The two eventually slayed one another in the light of a dying sun. (PROSE: The Paradox Moon)

During the Time War, the Barber-Surgeon claimed to have encountered a Doctor who remembered a different past to that recalled by the War Doctor. According to the Barber-Surgeon, this Doctor had different recollections of his first meeting with Ian Chesterton and Barbara Wright, (AUDIO: The Horror) which matched one account of the event claiming it had begun with a car crash at Barnes Common. (PROSE: Doctor Who in an Exciting Adventure with the Daleks)

Among the alternate timelines contained within the Axis, two alternative Doctors were known to exist on alternative Gallifreys. (AUDIO: Disassembled, Forever) One lived on a Gallifrey where the Temporal Intervention Agency freely interfered in the affairs of other people and planets. This Doctor ran away but was later caught and tried, being reintegrated into Gallifreyan society and reaching the position of Lord Burner. (AUDIO: Disassembled) Another was known as Theta Sigma and lived on a Gallifrey where time travel had never been achieved, working as a commentator. (AUDIO: Forever)

As a fictional character
In at least two parallel universes, the Doctor was a fictional character in a television series called Doctor Who. These universes were visited by the Eighth and Eleventh Doctors. (COMIC: TV Action!, The Girl Who Loved Doctor Who)

In one reality, the TV show Doctor Who was cancelled before being broadcast, with its would-be creator later going mad and believing himself to be the Doctor. (AUDIO: Deadline)

Wholly alternative Doctors
Some versions of the Doctor had lives which echoed the N-Space Doctor's while having no obvious point of connection. For example, the Third Doctor and Sarah Jane Smith visited a parallel universe where they encountered identical counterparts of themselves who were criminals with no knowledge of time travel. The Doctor of this world did go by the name of "the Doctor", and resembled the Third Doctor, but seemed to be a human, having no knowledge of time-travel, the TARDIS, or extraterrestrials. (COMIC: Who's Who?) The Eighth Doctor glimpsed many alternative versions of himself while in the Omniversal Spectrum, including Doc Gallifrey, Tardis Tails, Quiquaequod, Theta Stigma, Joe Smith and a counterpart who was a cyborg. (COMIC: The Glorious Dead)

In one parallel universe, (COMIC: Fire and Brimstone) the Doctor was the secret child of Ulysses and Annalisse. This Doctor was named President of the Time Lords by his grandfather, Barusa, however his half-brother the Master seized the title due to a lack of proof of the Doctor's heritage, forcing the Doctor to embark on a search for his missing father. (PROSE: The Chronicles of Doctor Who?)

In one parallel universe, Gallifreyan history was different, marked by Auld Mortality whose incarnation in the Doctor's era was Quences, (AUDIO: Auld Mortality) instead of the equivalent figure in N-Space, the Other, whose modern-day reincarnation was the Doctor. (PROSE: Lungbarrow) This world's version of the First Doctor was an author who was delayed in leaving Gallifrey due to the machinations of Quences. (AUDIO: Auld Mortality) Before his granddaughter joined him, the Doctor's travels saw him frequently alter Earth's history. (AUDIO: A Storm of Angels)

In another parallel universe, a more ruthless Doctor became stranded on Earth in 2039 after losing his TARDIS on the DEEP. When the Doctor began trying to reclaim his TARDIS, he was shot by his surrogate daughter Ruth Mills after she discovered that he had killed her biological father. The Doctor regenerated into a new body only for Ruth to kill that incarnation as well, a pattern she swore to repeat as long as was necessary. (AUDIO: Full Fathom Five) Similarly, in one parallel universe, Kate Stewart knew the Doctor as a man who went about annihilating "pathetic, pacifist aliens". (AUDIO: False Negative)

In one universe, the Doctor was known as the Pilgrim. In another, they were known as the Wanderer. (AUDIO: The Key To Key To Time)

Divergent Doctors
However, other alternative Doctors' lives branched off directly from particular point in the conventional Doctor's lifetime. Another of the timelines seen by the Eighth Doctor was one where he accepted Grace Holloway's offer to live with him on Earth as a couple (COMIC: The Glorious Dead) instead of spurning her. (TV: Doctor Who) In one parallel universe, the Doctor was killed by River Song who fulfilled her programming, (AUDIO: The Two Rivers) instead of rejecting it as occurred in N-Space. (TV: Let's Kill Hitler)

On the Inferno Earth, the Second Doctor had chosen one of the faces that the Time Lords had offered him at his trial. Arriving in the 1930s instead of the 1970s, the Doctor became an ally of Oswald Mosley and eventually took Mosley's place as the Leader, later becoming Great Britain's ruler. (PROSE: I, Alastair, Timewyrm: Revelation)

Whilst battling the Lamprey, the Sixth Doctor worked with several counterparts of his current incarnation, including a version travelling with Melanie Baal and another travelling with a counterpart of Mel Bush from an Earth where the Roman Empire had never fallen. The Doctors worked together to overload the Lamprey with their chronon energy, which cost many of them their lives. (PROSE: Spiral Scratch)

In one parallel universe, the Third Doctor was killed in an explosion whilst encountering the Silurians, though peace between humanity and the Silurians was still achieved. The Seventh Doctor of N-Space later visited this Doctor's grave. (COMIC: Final Genesis)

In the Unbound Universe, the Doctor, as in N-Space, was exiled to Earth following his Malfeasance Tribunal, but arrived in 1997 instead of the 1970s, creating a radically different timeline for Earth. (AUDIO: Sympathy for the Devil) This Doctor was left as the ruler of his universe after the Great War wiped out his people, (AUDIO: The Library in the Body) and later became stranded in N-Space in the company of Bernice Summerfield. (AUDIO: The True Saviour of the Universe)

In one universe, a version of the Doctor was placed on trial in circumstances matching (AUDIO: Exile) the trial of the Second Doctor following the War Chief incident, (TV: The War Games) although he sounded somewhat different. Killing himself in an escape attempt, he regenerated into a female incarnation who led from the Time Lords but was later captured, imprisoned in her TARDIS which would dematerialise her if she tried to take off. This Doctor was told that the controls were not set so and she took the chance to take off. (AUDIO: Exile)

In one reality, Sarah Jane Smith convinced the Fourth Doctor fulfill his mission to avert the creation of the Daleks. Caught off-guard by the temporal shockwave, the Doctor was unprepared for an already created prototype Dalek which exterminated Sarah and Harry. Already morose at having committed genocide, the Doctor allowed himself to be exterminated only to be time scooped to Gallifrey. Awakening, the Doctor was met by Narvin who surreptitiously gave him the Elixir of Life to allow him to regenerate while informing him that the mission had failed and the Time Lords were now in a Time War as a result of the changes to history. Unwilling to allow Sarah and Harry's deaths to be in vain, the Doctor accepted the regeneration and cast aside his former alias, renaming himself "The Warrior". (AUDIO: Dust Devil) The Warrior later became President of the Time Lords. (AUDIO: The Difference Office) At the end of the Time War, the Warrior renounced his new title, choosing to become the Doctor again as he removed himself from time, alongside Davros so that the conflict could end. Unexpectedly however, the Doctor found he had averted the Time War entierly, resuming his travels with Sarah and Harry. (AUDIO: The Key To Key To Time)

"Doctor Who"
The use of the name "Doctor Who" when referring to the Doctor is commonplace in the British media, the end credits of many episodes, and most prose and comic stories of the 1960s and 1970s. The ending credits for the series gave his name as "Doctor Who" or "Dr. Who", from 1963 until Logopolis part four, when incoming Doctor Peter Davison insisted upon a change in the credits of Castrovalva to "the Doctor", which remained in place until the end of the original series in 1989; executive producer Russell T Davies used "Doctor Who" when the series returned in 2005, but Tenth Doctor actor David Tennant asked to change it back to "the Doctor" beginning with The Christmas Invasion. Despite these insistences, both Davison and Tennant called the character "Dr. Who" in several different interviews, as is common for media and cast members.

Especially in the 1960s and early 1970s, many stories referred to the Doctor as "Doctor Who". The Doctor Who annuals and Target Books novelisations frequently called him "Doctor Who" in titles and narration, though dialogue between characters usually used "the Doctor". In The War Machines, WOTAN directly referred to the Doctor as "Doctor Who", but most other usages of the name throughout the series' history were non-serious, such as the Second Doctor's pseudonyms and K9's jokes. In World Enough and Time, told Bill Potts that the Doctor originally called himself "Doctor Who"; the Twelfth Doctor told Bill that Missy was trying to wind her up, but never denied the claim, and later in the episode explicitly self-identified as such.

"All stories are true"
Since the Doctor Who universe is an expansive playground for writers, subject to multiple rights holders, it's often prone to contradiction. Quite often, stories will provide incompatible accounts of retroactive continuity. As the head of the franchise, this has affected the Doctor more than anyone. Early on in Doctor Who history, for instance, the First Doctor had a second life as Dr. Who in his TV Comic run, where it's suggested he's a human time traveller. This did not contradict anything previously stated within the series (from TV: "An Unearthly Child", we only know the Doctor came from "another time, another world", and the Doctor insinuates he is a human throughout the William Hartnell era).

Some stories have attempted to establish that, say, the Eighth Doctor's adventures in the BBC Eighth Doctor Adventures and his Big Finish audio stories each belong to separate continuities, while others have ignored this, making reference to both continuities in one breath. Different stories also give different ideas of the Doctor's early life, often including incarnations from before the First Doctor, like the so-called Morbius Doctors. There's even been the suggestion that the Doctor was a reincarnation of the Other, posited by the VNAs, while other stories give the Doctor birth parents.

After 2020's The Timeless Children aired, introducing pre-Hartnell Doctors to mainstream continuity (even more directly than in The Brain of Morbius), some writers, like Russell T Davies, decided that "all stories are true now", meaning that all versions of the Doctor have equal claims to "existence". As a result, Davies published PROSE: Doctor Who and the Time War, initially planned for Doctor Who Magazine in 2013, but scrapped as it contradicted TV: The Day of the Doctor, involving a "parallel [continuity]" in which the Eighth Doctor ended the Time War using the Moment.

Casting
Up until 2019, every actor to portray the Doctor on an ongoing basis was Caucasian and born in the United Kingdom. However, the first Doctors of colour were introduced in Fugitive of the Judoon and The Timeless Children, respectively. Every actor until Jodie Whittaker had been male.

Despite the fact that the Doctor is not a native of Britain, or of Earth for that matter, every actor to play them so far has had a British accent, much in the way most aliens in the Star Trek franchise tend to speak with an American accent. The type of British accent has varied from one incarnation to the next. The earliest incarnations used RP, whereas some of the more recent incarnations have had Estuary accents. The Ninth Doctor had a Northern accent, causing Rose to ask why an alien would have a Northern accent, to which he replied, "Lots of planets have a north." (TV: Rose) Both Sylvester McCoy and Peter Capaldi used their natural Scottish accents while playing the role, with the fact the Doctor sounds Scottish being used in dialogue plot points in (to date) TV: Deep Breath and Robot of Sherwood. The Thirteenth Doctor had a Yorkshire accent. (TV: Twice Upon a Time)

To date, the oldest actor to be cast as the Doctor has been John Hurt, who was 73; the youngest has been Matt Smith, who was 26 when cast. The oldest to be cast on an ongoing basis was Peter Capaldi, who was 55 when he was cast and began filming, and turned 56 during the production of Series 8. In 2014, Tom Baker turned 80 and continued to record new performances as the Doctor for Big Finish Productions' Fourth Doctor Adventures audio dramas, making him the oldest actor to play the part in an officially licensed capacity. Peter Davison, Colin Baker, Sylvester McCoy and Paul McGann, all in their sixties or seventies, also continue to portray the Doctor in licensed audio dramas produced by Big Finish, with McGann also appearing in audio dramas produced by Big Finish and BBC Radio for broadcast on BBC7 radio. In the 2000s and 2010s, Tom Baker also portrayed the Doctor in AudioGO's Hornets' Nest, Demon Quest and Serpent Crest audio dramas.

In the Sarah Jane Adventures episode Death of the Doctor Part 1, Daniel Anthony, who plays Clyde Langer, became the first non-Caucasian actor to play the Doctor, when Clyde's body is briefly taken over by the Eleventh Doctor's consciousness. Anthony delivered a line of dialogue as the Doctor while impersonating Matt Smith's voice. Owing to the brevity of the performance, and the fact he is playing an established incarnation, the fact Anthony was the first to break the barrier of skin colour is generally not recognised. Aged 22 at the time the episode was filmed, Anthony was at the time the youngest to play the part.

Although the character has predominantly been portrayed as white, Jo Martin has portrayed an incarnation who is of colour, as have other uncredited supporting artists. (TV: Fugitive of the Judoon, The Timeless Children) Prior to this, there had been black actors who were considered for the role. Among them comedian Eddie Murphy, Charles Venn and Robbie Gee. Paterson Joseph auditioned for the part of the Eleventh Doctor. Additionally, Steven Moffat has stated that he offered the role of the Doctor to a black actor - though which incarnation is unknown.

Longest-serving Doctor
There are several different methods for calculating who was the "longest serving Doctor". The most commonsensical definition is simply that of the actor who played the role on television for the longest continuous period. This mantle goes to Tom Baker, who was the Fourth Doctor from June 1974 to March 1981, for 6 years, 9 months. Baker is also the longest-serving Doctor in terms of the number of individual episodes, total story count and amount of screen time. Thus he is generally considered to be the "longest-serving Doctor".

But there are other methods of measurement — all of which exclude Dimensions in Time.


 * For 92 of the 104 Saturdays that comprised 1964 and 1965, William Hartnell's credit appeared after each episode of Doctor Who without fail. He did sometimes take a holiday and pre-film the odd insert, filming for all but six weeks in both 1964 and 1965.
 * Peter Davison holds the record for the greatest length of time between his initial performance in the last episode of Logopolis, and Time Crash. The two events were separated by 26 years 8 months. Though he is not playing the same incarnation of the Doctor, Tom Baker's appearance as the Curator in The Day of the Doctor as a possible future version of the Doctor could mean his tenure in the role was longer than Davison's by this measure, with the gap between the 50th Anniversary special's broadcast and Baker's first appearance being just 8 months short of 40 years.
 * Colin Baker had the longest run between bookending regeneration scenes. The span from the premiere of The Twin Dilemma to his regeneration in The Brink of Death was approximately 31 years.
 * Paul McGann was notionally the longest-serving incumbent in the role, as he debuted in May 1996 and Christopher Eccleston's premiere didn't happen until March 2005. Being very generous, therefore, McGann was the "current Doctor" for a total of 8 years and 10 months. However, this is probably stretching a point, since obviously he was actually replaced not once but twice by the BBC. He effectively lost his incumbency once Richard E Grant was cast as the Shalka Doctor.
 * McGann also has recorded by far the greatest amount of hours of Doctor Who audio stories. Previously, he had more performed material on audio and television combined than even Tom Baker, but in 2010, Baker began recording audio dramas for AudioGO and then Big Finish, and had reclaimed his title by 2015.
 * The Eighth Doctor, though not McGann himself, is the longest-serving incumbent comic strip Doctor, in terms of the amount of time between his debut in Dreadnought on 1 June 1996, and his final appearance in The Flood on 2 March 2005, totaling 8 years and 9 months.
 * The Tenth Doctor is the longest-serving comic strip Doctor, in terms of the total number of stories which featured his incarnation. This is primarily due to the number of different publications that were granted comic licences during David Tennant's tenure in the role. Most of this count is due to the prolific comic strip published in Doctor Who Adventures which, for most of Tennant's tenure, was a weekly publication that ran a new standalone story every issue.
 * The Eleventh Doctor has the largest number of individual stories across all media.
 * The situation with books is a very close battle between the Seventh and Eighth Doctors, both of whom had long-running series. However, the Eighth Doctor is the longest-running both in terms of time and number of books published.

The issue of the longest-serving Doctor was a source of controversy on British game show, which asked the question with the choices of McCoy, McGann, Eccleston, and Tennant; the team split their £650,000 between McCoy and McGann, only to find out that the "correct" answer was Tennant. Once the error was discovered (partly since the question was fundamentally flawed due to the absence of Tom Baker), the team was brought back to continue where they left off with £325,000 and ended up winning £25,000.

Analogous characters
There have been several characters outside the confines of the legal DWU which have been broadly modelled on general aspects of the Doctor. Such "pastiches" are examined in greater detail elsewhere.

Perhaps more interestingly, other characters within the DWU, and who have in some cases met the "real" Doctor, have also sometimes been conceptualised as pastiches of the character of the Doctor. Sabbath Dei was envisioned by Lawrence Miles as the individual who took on the role of the Doctor in the post-War universe, although he was later developed into a more villainous figure. Iris Wildthyme is not only a mildly ironic pastiche of the Doctor, but is, thanks to her metafictional qualities, aware of it, and The Scarlet Empress has the Doctor himself act with mild annoyance around Iris precisely due to his knowledge that she is duplicating his own life.

The Doctor's wives
Steven Moffat, in his production notes column in DWM 482, speculated that the Doctor's first spouse out of the four mentioned in the television story Death in Heaven was a woman who was married to the First Doctor for a long time on Gallifrey and bore the Doctor's children. He claimed "Mrs Who No 1" was never mentioned by the Doctor nor has he ever discussed her.

Jelly Babies
See main article 'Jelly baby'

One of the longest running gags of the series is the Doctor's penchant for jelly babies. Multiple incarnations have attempted to offer them to others, be it to comfort them (such as in TV: Robot) or distract them (such as in TV: The Pirate Planet). This gag was particularly evident during the Fourth Doctor era.

"You've redecorated..."
Another long running gag was the Doctor observing a change in a familiar room or building, and stating that they "don't like it". This gag was commonly done when an earlier incarnation of the Doctor entered a newer incarnation's TARDIS.

Instances of this gag occurring include:


 * The Second Doctor looking around the console room of the Third Doctor's TARDIS and Colonel Charles Crichton's office before both times stating "I don't like it!" (TV: The Three Doctors, The Five Doctors)
 * The Tenth Doctor observing the differences between his own console room and that of the Eleventh Doctor before expressing his dislike. (TV: The Day of the Doctor)
 * The Eleventh Doctor seeing Craig Owens' new house, unaware that he had moved. (TV: Closing Time)
 * The First Doctor describing the Twelfth Doctor's TARDIS as "hideous". (TV: Twice Upon A Time)

The only character other than the Doctor to deliver a variation of this quote was Clara Oswald, on her entrance to the Twelfth Doctor's console room. (TV: Deep Breath)

An inverse version of this gag has also occurred, when the Thirteenth Doctor looked around her TARDIS's new console room and gleefully stated "I like it!" (TV: The Ghost Monument)

Vehicles owned by the Doctor
See main articles Bessie and the Whomobile.

As well as the TARDIS, the Doctor was the owner of two earthbound vehicles, named Bessie and the Whomobile (the latter name not used in-universe). These were most prominently used by the Third Doctor during his exile on Earth (for example, TV: Doctor Who and the Silurians, Invasion of the Dinosaurs), though they have also been used by later incarnations when required (for example, TV: Robot, Battlefield).