In AD 311 the Roman Empire stands on the brink of civil war. The unity established by the emperor Diocletian decades before has collapsed, and now four rivals contend for supreme power.
In the west, Constantine controls Gaul, Spain, Britain and the Rhine frontier. Licinius commands the central Danubian provinces, Greece and the Balkans, while Maximinus Daza rules the east and Egypt. Between them the usurper Maxentius, son of the former emperor Maximian, possesses the city of Rome itself, with Italy and North Africa.
The rival emperors prepare their troops and negotiate their alliances. All know that the coming war will decide the future of the Roman world.