Emperor

An emperor was a male monarch, usually the sovereign ruler of an empire or another type of imperial realm. (TV: Nightmare in Silver)

An empress, the female equivalent, could be an emperor's wife (empress consort) or, in Queen Victoria's case, a woman who ruled in her own right (empress regnant). (TV: Tooth and Claw) An empress' husband was sometimes an emperor consort. (AUDIO: Empire of the Racnoss) Emperors were generally recognised to be of a higher honour and rank than kings.

Emperors and their domains
One Racnoss Empress had one emperor consort before she chose a new emperor. (AUDIO: Empire of the Racnoss)

The Dalek Emperor ruled the Dalek Empire. There were at least six different Dalek Emperors, notably including Davros, (TV: Remembrance of the Daleks) the Golden Emperor, (COMIC: Invasion of the Daleks) the Emperor of the Restoration, (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe) and the Dalek Emperor in the Last Great Time War. (TV: The Parting of the Ways)

There was a Cyber-Emperor, who ruled over the Cyber-Empire, (COMIC: Kane's Story, Frobisher's Story) and a Uvodni Emperor who ruled the Uvodni Empire. (TV: Warriors of Kudlak)

In the post-War universe, the universe was ruled by the Emperor, one of the surviving elementals, from the Needle. (PROSE: Father Time)

On Earth, the leader of the Roman Empire was called Caesar, beginning with Julius Caesar. Nero, (TV: The Romans) Augustus, Tiberius, (AUDIO: 100 BC) Claudius, (PROSE: Of the City of the Saved...) Hadrian, (AUDIO: Many Happy Returns) and Valentinian were Caesars. (PROSE: Combat Magicks) In the Empire of Empires, the Caesar of Roma I was given the title Prime Emperor. (PROSE: Warlords of Utopia)

Justinian was Emperor of Byzantium in 540. (PROSE: The Secret History)

Kublai Khan was Emperor of the Mongols and China. (TV: Marco Polo)

Ludens Nimrod Kendrick Cord Longstaff XLI was the Emperor and Defender of Humanity and Imperator of Known Space. (TV: Nightmare in Silver)

The nation of Japan also had its own Japanese emperor while the prominent power in Asia during the first half of the 20th century. (PROSE: The Shadow of Weng-Chiang)

Charlemagne reigned over the Holy Roman Empire (PROSE: The Lonely Computer) and Franz Joseph was emperor over Austria. (AUDIO: The Silver Turk) Napoléon Bonaparte was the Emperor of France. His nephew, Napoleon III, was emperor in the 1860s. (PROSE: World Game)

Ludens Nimrod Kendrick Cord Longstaff XLI was a human emperor, known as the imperator of space. (TV: Nightmare in Silver)

In a timeline where River Song caused time to collapse when she refused to kill the Doctor, Winston Churchill was the Holy Roman Emperor in Britain. (TV: The Wedding of River Song)