Domitian, Roman emperor, son of Vespasian, brother of Titus, whom he succeeded in 81, the last of the twelve Cæsars; exceeded the expectations of every one in the beginning of his reign, as he had given proof of a licentious and sanguinary character beforehand, but soon his conduct changed, and fulfilled the worst fears of his subjects; his vanity was wounded by the non-success of his arms, and his vengeful spirit showed itself in a wholesale murder of the citizens; many conspiracies were formed against his life, and he was at length murdered by an assassin, who had been hired by his courtiers and abetted by his wife Domitia, in 96.