The poem begins with Constantine, emperor of Rome, riding out to battle the Huns and Hrethgoths. He is a mighty king made strong by God, though he is not aware of the Christian God yet. He sees a vision in the sky and he is told that he will halt his enemies with the symbol that is shown to him by the heavens. The battle begins and Constantine reveals the symbol that he was shown, a cross. The cross sends his enemies running in all directions and they are easily defeated by the Romans.