Constantine the Great | When Did the Roman Empire Become Christian?
The Fourth Century marks critical elements of Church development as foundational doctrines were being formulated at ecumenical councils and as Christianity was becoming an integral part of the empire after centuries of persecution. The fourth century marks the birth of monasticism in Egypt and its proliferation throughout the Roman Empire.
After a long and complex history of internal battles within the empire, Constantine (272-337) became the Roman emperor. According to Eusebius, Constantine beheld a vision of a cross with which he would conquer. Constantine marked his banners with the sign of the cross and triumphed in battle. When he became emperor, he decreed that there would be a policy of religious toleration of Christianity in the Edict of Milan in 313. Theodosious the Great was one of his successors who made Christianity the official state religion. The Christening of the Roman empire brought waves of persecution to a halt and Christianity flourished.