The First Thousand Years: A Global History of Christianity

by Robert L. Wilken

So he gathered his army, crossed the Alps, and marched purposefully and deliberately toward Rome, where Maxentius and his army were waiting. What happened next is a matter of great dispute. A Christian account written shortly after the battle reports that in a dream Constantine was instructed to “mark the heavenly sign of God” on the shields of his soldiers before taking the field. The sign was the letter X with a vertical stroke through it. Armed with this sign, Constantine’s soldiers gained the victory. But a later account by Eusebius based on Constantine’s own report to him says that the sign appeared in the heavens during the day, in fact in the afternoon when the sun was beginning to wane, and that it was also seen by the army. All were astounded at the sight, and Constantine was at a loss as to what it meant. According to Eusebius’s account this unusual spectacle in the sky did not take place at the Milvian Bridge up the Tiber River from Rome, but when Constantine was on the march with his troops elsewhere, probably in Gaul. A third account in a panegyric of Constantine written by a Roman orator, dated two years earlier in 310, also says the event took place on a march and what Constantine saw was the sun God Apollo surrounded by a circle or wreath of light.