Time Wars

The Time Wars were an ancient era of Gallifreyan history marked by numerous conflicts wherein the Time Lords ensured their supremacy, eradicating all other lifeforms with the potential for time travel. (PROSE: Sky Pirates!, The Gallifrey Chronicles, Heart of TARDIS) The Time Wars lasted for 30,000 years on 1000 planets, becoming a "nightmare of contradiction, paradox, and death." (PROSE: The Infinity Doctors)

Campaigns of the Time Wars period included the Black Sun War, (COMIC: 4-D War, PROSE: Heart of TARDIS) the Eternal War, and the Racnoss Wars. (PROSE: River of Time, et al.)

Ultimately, the Time Wars ended in Time Lord victory. These conflicts helped to lay the foundations for the rationalistic universe of the Doctor's era, (PROSE: The Infinity Doctors) as part of what would later be known as the anchoring of the thread. (PROSE: The Infinity Doctors, Christmas on a Rational Planet, The Book of the War)

Overview of the Wars
The Doctor once claimed the Time Wars were fought a generation or so after Rassilon, (PROSE: The Infinity Doctors) but the Time Wars era included even Rassilon's founding of Time Lord civilisation. The Fourth Doctor mentioned that Rassilon discovered the secrets of time by stealing the translation belt of a species who attacked Gallifrey in the Time Wars "in retaliation for things we did to them before we'd even heard of them in the first place." (PROSE: Heart of TARDIS) Such an event occurred during the Disappearance of Omega involving the Order of the Black Sun. (COMIC: Star Death) However, it would not be until 30 years later when the next generation of Time Lords would inadvertently cause the Order to war against Gallifrey. (COMIC: 4-D War, Black Sun Rising)

Gallifrey of this early era was characterised by such stimuli as "the stink of steaming grease from the first breeding engines, the marching chants of the first parahuman brigades, and the songs of the killer cats in the south." (PROSE: Hark! The Herald Angels Sing) One parahuman mercenary group, the Special Executive, had significant involvement in the Black Sun War. (COMIC: 4-D War, Black Sun Rising)

The Time Wars began concurrently with the Rutan-Sontaran War. (PROSE: The Infinity Doctors) The Sontaran Brilox was involved in instigating the Black Sun War on Desrault. (COMIC: Black Sun Rising)

The Fourth Doctor told Wblk that he had been at the Time Wars as an eyewitness. (PROSE: Heart of TARDIS) The Fifth Doctor later became involved in the Racnoss Wars. (AUDIO: Empire of the Racnoss)

Those species which Gallifrey could not conquer became allied with the Time Lords in their war, the Fledgling Empires (PROSE: A Brief History of Time Lords) or Alliance of Races. (COMIC: Terrorformer) The Qwerm were among those who joined the Time Lords in fighting the Great Vampires, Racnoss, and "whatever other races wanted to sweep across the universe like a plague". (PROSE: River of Time)

Once the Time Lords achieved victory in their initial wars, they realised that they had caused the permanent militarisation of those species they allied with, creating "a new generation of problems" to be eradicated. The Qwerm hid before they could be destroyed by the Time Lords. (PROSE: River of Time)

Gallifrey developed a planet-sized warship armed with the Cold, but ultimately never got the chance to use it. (PROSE: The Infinity Doctors, Interference)

Ultimately, after thirty-thousand years of conflicts, "certain higher powers" stepped in to stop the devastation before it destroyed the universe. (PROSE: The Infinity Doctors)

Targets of the Time Wars
Entire future species and whole orders of species were destroyed; Time Lords of this era successfully fought against the Charon, (PROSE: Sky Pirates!) Great Vampires, Narlok, Racnoss, (PROSE: River of Time) Order of the Black Sun, (COMIC: 4-D War, PROSE: Heart of TARDIS) Vondrax, (AUDIO: Enemy Lines) and countless other "nameless races" of which no record survived. (PROSE: Sky Pirates!, River of Time) Additionally, many parallel Gallifreys were erased from existence. (PROSE: The Infinity Doctors)

Vampires
Some accounts place the Eternal War against the Great Vampires as beginning or continuing into the early era of the Time Lords, (PROSE: The Multi-Faceted War, The Book of the War) having lasted over a thousand years. (PROSE: The Pit) The Eighth Doctor, when telling James Macfarlane of the Vampire War, mentioned that it was just one of many wars fought by the Time Lords at the time. (AUDIO: The Scent of Blood) Atraxi was the sole Gallifreyan warrior to return from the Eternal War; he tried to warn the now-scientific Time Lords that the War would continue and they weren't safe from "the Monsters", but quickly died from Rassilon's plague. (PROSE: The Pit)

Racnoss
The Ra'ra'vis captured Rassilon while he was on a military trip against the Racnoss and tried to force him into giving them time travel. Rassilon was rescued by Vogans. (PROSE: Jorus and the Voganauts)

Rigelans
The Order of the Black Sun existed thirty-thousand years after Omega's death, (COMIC: Star Death) at the end of the Time Wars. (PROSE: The Infinity Doctors)

Other
Other targets of the Time Lords included the Narlok. (PROSE: River of Time)

Aftermath
Artifacts of the Time Wars remained strewn across history, (PROSE: Sky Pirates!, River of Time, Damaged Goods, AUDIO: The Scent of Blood) as well as many lone survivors of races targeted by the Time Lords in this time. (PROSE: Sky Pirates!, The Gallifrey Chronicles, River of Time, TV: State of Decay, The Runaway Bride, COMIC: Terrorformer) By the era of Ulysses, Mister Saldaamir was considered the last survivor of the Time Wars. (PROSE: The Gallifrey Chronicles)

The title "Time Wars" was retroactively applied to this era of Gallifreyan history. (PROSE: Sky Pirates!) Time was stabilised after the Time Wars, but the Time Lords were forced to seal off whole areas of time and space which were damaged beyond repair. (PROSE: The Infinity Doctors)

One reality bomb remained drifting in the Horsehead Nebula for fifty billion years before catching the Seventh Doctor's TARDIS. (PROSE: Sky Pirates!)

By some point, the Time Lords co-existed as Higher Evolutionaries alongside other powerful time-aware factions, (COMIC: The Tides of Time) even the Order of the Black Sun. (COMIC: The Final Chapter)

Wblk claimed the Time Wars didn't happen. (PROSE: Heart of TARDIS)

During the War in Heaven, Time Lords revived and augmented ancient biological defenses created during previous time wars against threats such as the Charon and the Great Vampires. (PROSE: The Ancestor Cell)

Behind the scenes

 * Lance Parkin submitted an entry for The Book of the War, later published in the fan magazine Myth Makers, which included further information on the Time Wars as they pertained to Mister Saldaamir. Saldaamir's home planet was "unhappened" in the Time Wars and he lost his memory, family, friends, and companions. He survived by rooting himself to a new location by hastily marrying a passing witch, similarly to how the Eighth Doctor survives the unhappening of Gallifrey by rooting himself to Earth through marrying Scarlette in PROSE: The Adventuress of Henrietta Street.
 * Lance Parkin, having in PROSE: The Infinity Doctors equated the anchoring of the thread described in PROSE: Christmas on a Rational Planet with the Time Wars as they'd been defined in PROSE: Sky Pirates!, continued to equate the two in AHistory. However, after The Infinity Doctors, The Book of the War expanded upon the anchoring seen in Christmas and indicated it took place on a single day and marked the start of the Eternal War, contradicting Parkin.
 * The Time Wars are described in Jacob Black's My Best Enemy..., published in the charity anthology Unbound: Adventures in Time and Space, as involving "Rassilon's specially woven armies of crusaders" and having been over in an instant. The Lords of Althrace are posited as having only survived the Wars due to Rassilon requiring the harmonic effects of their Event Synthesizer.