Ptolemy Caesar
Ptolemy Caesar, nicknamed Caesarion, was the son of Pharaoh Cleopatra VII. (PROSE: State of Change, The Last Pharaoh)
In the normal historical course of events, his father was the Roman Imperator Julius Caesar. He had three younger half-siblings by his mother and Mark Antony. A year after his mother's suicide he was murdered by Octavian. (PROSE: The Last Pharaoh) However, the alternate Rome Terra Nova, created by the Rani using the power of Iam, was home to an alternative Caesarion, the son of Mark Antony and Cleopatra. After the Sixth Doctor managed to move Terra Nova to a new solar system, allowing it to continue existing in the universe separate from the normal Earth, this Ptolemy Caesar became its peaceful ruler. (PROSE: State of Change)