Head from the Colossal Marble Statue of Constantine the Great

Flavius Valerius Aurelius Constantine (c. 272 - 337), better known as Constantine the Great, was perhaps the most important person in the development of the early Christian Church (after Jesus and Paul, naturally). He ultimately gave Christianity political and social legitimacy in the Roman Empire, thus allowing the young religion to establish itself, obtain powerful patrons, and ultimately dominate the Western world.

Constantine was born at Naissus, in Moesia (now Nish, Serbia) and was the oldest son of Constantius Chlorus and Helena. Constantius served in the military under emperor Diocletian and emperor Galerius, distinguishing himself both in Egyptian and Persian campaigns. When Diocletian and Maximian abdicated in 305, Constantius and Galerius assumed the throne as co-emperors: Galerius in the East, Constantius in the West.