King

The title of king was given to the head of state in a monarchy. This title was often restricted to men, with women in the equivalent position being called queen, although this was not always the case. (TV: The Next Doctor, Brave-ish Heart) Kings were addressed as Majesty. (AUDIO: The Death of Captain Jack)

The Twelfth Doctor indicated that he might become a king or queen in the course of his travels. (TV: Death in Heaven)

Kings and their domains
In 2700 BC, Gilgamesh was king, in his own words, of "Ur, Uruk, and just about everywhere else worth knowing..." (PROSE: Timewyrm: Genesys, Happy Endings)

Ancient Egypt had several Pharaohs, or kings, including Amenhotep II, Thutmose IV, (AUDIO: The Eye of the Scorpion) Rameses II, (PROSE: Byzantium!) Tut-Ankh-Amen, (PROSE: The King of Golden Death) Ptolemy I (COMIC: Voyager) and Caesarion. (PROSE: The Last Pharaoh)

Priam was the king of Troy during the Trojan War in circa 1200 BC. (TV: The Myth Makers)

Tarquin the Proud was the last king of the Roman Kingdom. Soon after he purchased three Sibylline books from a Tenctrama, the Senate took charge of Rome. (PROSE: Combat Magicks)

Alexander the Great was king of Macedon in the 4th century BC. (AUDIO: Farewell, Great Macedon)

Prasutagus was king of the Iceni tribe in the 1st century AD. (AUDIO: The Wrath of the Iceni)

Attila was king of the Huns in 451. (PROSE: Combat Magicks)

Egfrith was king of Mercia in 785. (PROSE: The Dying Days)

England had many kings, including Arthur, (PROSE: The Creation of Camelot) Alfred the Great, (PROSE: Revenge of the Judoon) Athelstan, (TV: Planet of the Dead) Ethelred, (PROSE: The Immortals) Cnut, (AUDIO: Invaders from Mars, The Spirit Trap) Edward the Confessor, Harold Godwinson, William I, (TV: The Time Meddler) Richard I, (TV: The Crusade) John, (TV: The King's Demons, PROSE: A History of Humankind) Richard II, Henry IV, (AUDIO: The Doctor's Tale) Edward IV, Edward V, Richard III, Henry VII, (AUDIO: The Kingmaker) Henry VIII, (TV: The Sensorites, The Power of Three) Edward VI (TV: The Coach with the Dragon Tattoo) and William IV. (PROSE: The Time Traveller's Almanac)

Prior to 1066, Cnut was king of Denmark. (PROSE: The Real Hereward)

In the 11th century, Harald Hardrada was the king of Norway who led a Viking invasion of England in 1066. (TV: The Time Meddler)

James V was the king of Scotland in 1540. (TV: Tooth and Claw)

James I and VI, (PROSE: The Empire of Glass) Charles I, (AUDIO: The Roundheads) Charles II, (TV: The Impossible Astronaut) James II and VII, and William of Orange were kings of both Scotland and England. (AUDIO: The Glorious Revolution)

George I and George II were kings of Great Britain. (TV: The Highlanders)

The United Kingdom of Great Britain and Ireland (later the United Kingdom of Great Britain and Northern Ireland) had kings, such as George III, Edward VII, George V, Edward VIII, George VI, Charles III and William V. Henry XII was a "drinking buddy" of the Doctor. (TV: The Beast Below)

Philip II was the king of Spain in the 16th century, and was married to Queen Mary I of England. (AUDIO: The Marian Conspiracy)

France had kings, including Philippe Auguste, (AUDIO: The Church and the Crown) Francis I, (COMIC: Art Attack) Charles IX, Henri III, (TV: The Massacre) Louis XIII, (AUDIO: The Church and the Crown) Louis XIV, (COMIC: Terror of the Cabinet Noir) Louis XV, (TV: The Girl in the Fireplace) and Louis XVI. (PROSE: The Reign of Terror) However, the French monarchy was abolished after the French Revolution. (TV: The Reign of Terror) The French monarchy was restored for a period of time, until King Louis-Philippe abdicated in 1848. (PROSE: World Game)

There was a King of Sweden in 1580. (TV: The Vampires of Venice) Oscar was King of Sweden in the late 19th century. (AUDIO: Grand Theft Cosmos)

Sultan was a title equivalent to king in various Earth cultures. Saladin was a Saracen Sultan of Egypt and Syria in the 12th century, (TV: The Crusade) and Mehmed II was a sultan of the Ottoman Empire in the 15th century. (AUDIO: Son of the Dragon) This title also used on other planets, such as Dellah, where the Tashwari had a sultan. (PROSE: Oh No It Isn't!)

The CyberKing was the name of both the Dreadnought-class ship and its controller, used to front a Cyberman invasion. In 1851, Mercy Hartigan became the CyberKing. She was one of the few female individuals to bear the title "King." (TV: The Next Doctor)

Rhodia had a king before the planet's population was wiped out by the Shadow Kin. (TV: For Tonight We Might Die)

The Shadow King was the monarch of the Shadow Kin and ruler of the Underneath. Corakinus was the Shadow King until he was defeated and displaced by the human April MacLean in 2016 who shortly lost the power after Corakinus broke the link between them. (TV: Brave-ish Heart) The Rhodian known as Charlie Smith briefly became the Shadow King after the deaths of April and Corakinus, but seemingly rendered the title defunct after his genocide of the Shadow Kin. (TV: The Lost)

Yrcanos was a warrior king of the Krontep in the 24th century. He later fell in love with Peri Brown. (TV: Mindwarp, The Ultimate Foe)

Peladon was the ruler of Peladon in the 41st century. (TV: The Curse of Peladon)

In the 54th century, King Hydroflax was a merciless conqueror and pillager. His subjects included the people of Mendorax Dellora and the Shoal of the Winter Harmony. (TV: The Husbands of River Song)

Adelebert was the monarch on Rigel Seven. (PROSE: Players)

The Eleventh Doctor briefly served as a king for the Kreech. (COMIC: The Cleverest King)

During his rule of Floor 1056, the Saxon Master "lived like a king" before the Mondasians overthrew him. (TV: The Doctor Falls)

Other realities
In an alternate timeline of his own making, John Hart married Queen Victoria and became prince consort, becoming king of the British Empire after her death, having disposed of her son the Prince of Wales. (AUDIO: The Death of Captain Jack)

In a more technologically advanced parallel universe, Edward IX was king of England in the 1970s. (COMIC: Who's Who?)