The history of Christianity begins with Jesus, an itinerant Jewish preacher and teacher, who was crucified in Jerusalem c. AD 30–33. His followers proclaimed that he was the incarnation of God and had risen from the dead. In the two millennia since, Christianity has spread across the world, becoming the world's largest religion with over two billion adherents worldwide.
Initially, Christianity was a mostly urban grassroots movement. Its religious text was written in the first century. A formal church government developed, and it grew to over a million adherents by the third century. Constantine the Great issued the Edict of Milan legalizing it in 315. Christian art, architecture, and literature blossomed during the fourth century, but competing theological doctrines led to divisions. The Nicene Creed of 325, the Nestorian schism, the Church of the East and Oriental Orthodoxy resulted. While the Western Roman Empire ended in 476, its successor states and its eastern compatriot—the Byzantine Empire—remained Christian.