It has been five years since Constantine was proclaimed Augustus by his father's legions in Britannia. Now he is locked in a savage war with Maxentius, son of Maximian. After a series of hard-fought battles in northern Italia, Constantine is marching on Roma, the ancient capital of the empire. Constantine receives a vision in his dreams. He sees a strange symbol and hears a voice telling him that it is a sign of victory and triumph. Constantine recognizes the symbol from an insignia which some of his soldiers mark on their shields. It is the Chi-Rho, which is used by Christians to secretly identify themselves to one another. Christianity has been proscribed since the days of the Emperor Diocletian. Many thousands of Christians have been executed by sword, fire, scourging and crucifixion until it seems that their religion would surely perish. Nevertheless, Constantine instructs his soldiers to paint the prohibited symbol on the fronts of their shields as a sign of their invincibility. Fourteen legions march toward Roma, proudly bearing the Chi-Rho emblazoned shields. Constantine's army meets the enemy at the Milvian Bridge, just outside of the city. The fate of the empire hangs in the balance. The course of history is about to change.