In 727 the yet existing letters of Pope Gregory II. to the emperor Leo exhibit that monarch as thoroughly possessed with the claim to govern the Church as he governs the State. In this he is as thoroughly encountered by the Pope, who calls up against him the unbroken tradition of the Church during the seven centuries, and reminds him of the sad misfortunes of those emperors who had attempted to carry their civil authority into the domain of revealed truth. The great eastern teacher, St. John of Damascus, then living in the Syrian court of the chalif, lays this down in language as peremptory as that of the Pope. The guilt of Leo III. is heightened by the fact that he had before him in the history of his own realm during the hundred years preceding him the rise of a religion essentially opposed to the Christian faith, which he was professing himself to purify. Its force, ever exercised against Christians with the utmost virulence and cruelty, was centered in the fact that its chief deduced all civil authority from the prophetic office of its founder. But while the kingship of Mohammed, as inherited by his chalifs, began with his attempt to found a religion, Leo, in continuing and advancing to their utmost tension the interferences of Justinian with the spiritual order, was undoing the ancient laws of the empire for a hundred and fifty years, from the time of Constantine to that of Zeno. His own patriarch, Germanus, chose rather to lay his omophorion on the altar, and depart into exile than sanction and accept Leo’s usurpation in sacred things. The whole liberty, and with it the whole existence of the Church, were comprehended in the resistance maintained by Pope Gregory, and attested by patriarch Germanus as a victim. Gregory II. followed, in giving to Cæsar the things of Cæsar, but to God the things of God, the whole line of his predecessors. Leo III. imitated wrongly the chief antagonist of the Christian name; but Mohammed was at least consistent with his original falsehood. In this his religion itself was contained. Likewise the whole work of Christendom was embodied in the victorious defence of Gregory against the consummation of eastern despotism.