Caesar

Caesar was the title held by the ruler of the Roman Empire beginning with Julius Caesar. Nero, (TV: The Romans) Augustus, Tiberius, (AUDIO: 100 BC; PROSE: Rome), Caligula, (PROSE: The Lonely Computer) Claudius, (PROSE: Of the City of the Saved...) Galba, Otho, Vespasian, (PROSE: The Romans) Trajan (PROSE: The Romans; COMIC: The Long Con), Hadrian, (PROSE: The Romans) Marcus Aurelius (TV: Deep Breath, The Day of the Doctor), Constantine I (AUDIO: The Council of Nicaea; COMIC: Conversion), Maxentius, (COMIC: Conversion) Valentinian (PROSE: Combat Magicks) and Justinian. (AUDIO: The Secret History)

"Caesar" was originally the family name of Julius Caesar. The Sixth Doctor and Evelyn Smythe met Julius Caesar's parents, Gaius Julius Caesar the Elder and Aurelia, in 101 and 100 BC. (AUDIO: 100 BC) After Julius Caesar's death, it became the title of the Roman Emperor. (TV: The Romans)

In an alternate timeline, Caesar was a title held by Holy Roman Emperor Winston Churchill. (TV: The Wedding of River Song)