Constantine I is the only Roman emperor called “The Great”. Born around AD 272 at Naissus, in modern Serbia, his father was Constantius I, one of the soldier emperors in the Tetrarchic system. On campaign in Britain the sick Constantius I died at York in AD 306 so the army proclaimed Constantine emperor. From AD 307 Constantine styled himself as “Augustus” and slowly but surely became the sole ruler of the empire. Notably, at the Milvian Bridge in AD 312, he defeated Maxentius with a Christian symbol on his soldier's shields, apparently given by God in a dream.
As he aged Constantine left the old gods behind, becoming Christian, and this support shaped our modern world as Christianity in the medieval era was the common cause that united the west. He was baptized just before his death in AD 337 at roughly 65.
