Life of Constantine

And besides this, he caused to be painted on a lofty tablet, and set up in the front of the portico of his palace, so as to be visible to all, a representation of the salutary sign placed above his head, and below it that hateful and savage adversary of mankind, who by means of the tyranny of the ungodly had wasted the Church of God, falling headlong, under the form of a dragon, to the abyss of destruction. For the sacred oracles in the books of God's prophets have described him as a dragon and a crooked serpent; and for this reason the emperor thus publicly displayed a painted resemblance of the dragon beneath his own and his children's feet, stricken through with a dart, and cast headlong into the depths of the sea.

In this manner he intended to represent the secret adversary of the human race, and to indicate that he was consigned to the gulf of perdition by virtue of the salutary trophy placed above his head. This allegory, then, was thus conveyed by means of the colors of a picture: and I am filled with wonder at the intellectual greatness of the emperor, who as if by divine inspiration thus expressed what the prophets had foretold concerning this monster, saying that “God would bring his great and strong and terrible sword against the dragon, the flying serpent; and would destroy the dragon that was in the sea.” This it was of which the emperor gave a true and faithful representation in the picture above described.