Mark. Latin name Marcus Antonius. ?83–30 bc, Roman general who served under Julius Caesar in the Gallic wars and became a member of the second triumvirate (43). He defeated Brutus and Cassius at Philippi (42) but having repudiated his wife for Cleopatra, queen of Egypt, he was defeated by his brother-in-law Octavian (Augustus) at Actium (31)