City of God

For the good God, lest men, who believe that He is to be worshipped with a view to eternal life, should think that no one could attain to all this high estate, and to this terrestrial dominion, unless he should be a worshipper of the demons—supposing that these spirits have great power with respect to such things—for this reason He gave to the Emperor Constantine, who was not a worshipper of demons, but of the true God Himself, such fullness of earthly gifts as no one would even dare wish for.

To him also He granted the honor of founding a city, a companion to the Roman empire, the daughter, as it were, of Rome itself, but without any temple or image of the demons. He reigned for a long period as sole emperor, and unaided held and defended the whole Roman world. In conducting and carrying on wars he was most victorious; in overthrowing tyrants he was most successful. He died at a great age, of sickness and old age, and left his sons to succeed him in the empire. But again, lest any emperor should become a Christian in order to merit the happiness of Constantine, when every one should be a Christian for the sake of eternal life, God took away Jovian far sooner than Julian, and permitted that Gratian should be slain by the sword of a tyrant.

But in his case there was far more mitigation of the calamity than in the case of the great Pompey, for he could not be avenged by Cato, whom he had left, as it were, heir to the civil war. But Gratian, though pious minds require not such consolations, was avenged by Theodosius, whom he had associated with himself in the empire, though he had a little brother of his own, being more desirous of a faithful alliance than of extensive power.