Aëtius, Flavius (396?-454), a Roman general who protected Gaul against repeated barbarian attacks. He repulsed the Visigoths, threw back the Franks, and in 451 won his most famous victory—over Attila's Huns at the battle of Châlons. Through intrigue and murder, Aëtius made himself actual ruler of the Roman Empire during the reign of Valentinian III. He was finally stabbed to death by the emperor.