The remainder of Rome's territory—if not its nature—was defended for several decades following 410 AD largely by Flavius Aëtius, who managed to play off each of Rome's barbarian invaders against one another. In 435 AD he led a Hunnic army against the Visigoths at the Battle of Arles, and again in 436 AD at the Battle of Narbonne. In 451 AD he led a combined army, including his former enemy the Visigoths, against the Huns at the Battle of the Catalaunian Plains, beating them so soundly that although they later sacked Concordia, Altinum, Mediolanum, Ticinum, and Patavium, they never again directly threatened Rome. Despite being the only clear champion of the Empire at this point Aëtius was slain by the Emperor Valentinian III's own hand, leading Sidonius Apollinaris to observe, "I am ignorant, sir, of your motives or provocations; I only know that you have acted like a man who has cut off his right hand with his left".