1700 years ago, Constantine was proclaimed emperor of the current new English city of York. That event was a real coup: the political order of the Roman Empire crumbles and the following years are characterized by struggles between various pretenders to the throne. Have died, Constantine, had been an actor most of history. But wins and this victory is attributed to a new god, he identifies with the God of Christians. In this biography, Hartwin Brandt tells the story of an amazing career in which the protagonist's religious orientation is characterizing the Roman Empire of late antiquity, with its imposition, begins a process that continues today worldwide.