Two Popes of weak ability had followed Damasus, and witnessed, rather than accomplished, the ruin of the old religion. It was Ambrose who had directed the convenient youth of Gratian and Valentinian II., and had dislodged the pagans and other rivals at the point of the spear. Innocent I. (402-417) was a greater man: an upright priest, an able statesman, a zealous believer in the divine right of Popes. Milman has finely drawn him serenely holding his sceptre at Rome while the Emperor cowered behind the fortifications at Ravenna. While Rome tumbled in ruins about him, he continued calmly to tell the bishops of Gaul and Spain and Italy what the "Apostolic See" directed them to do. His puny yet bombastic successor, Zosimus, maintained the solitary blunder, without the redeeming personality, of Innocent, and might have wrecked the Papacy if he had not died within a year or so. The worthier Boniface and still worthier Celestine restored Roman prestige in some measure, and, in 440, after the edifying but undistinguished Pontificate of Sixtus III., Leo the Great entered the chronicle. Leo, a Roman of Tuscan extraction, was the chief deacon of the Roman Church, and corresponded with Cyril of Alexandria on Eastern affairs. It was probably at his instigation that the learned Cassianus wrote his treatise _On the Incarnation of Christ_. In 440, Leo was sent by the Emperor to reconcile the generals Aetius and Albinus, who quarrelled while the Empire perished. Sixtus died in his absence, and Leo was unanimously elected to the Papacy. Toward the close of September he returned to Rome, and glanced about the troubled world which he had now to rule.