when did rome make christianity the religion of the empire
Constantine the Great and Christianity Constantine's decision to cease the persecution of Christians in the Roman Empire was a turning point for early Christianity, sometimes referred to as the Triumph of the Church, the Peace of the Church or the Constantinian shift. In 313, Constantine and Licinius issued the Edict of Milan decriminalizing Christian worship. The emperor became a great patron of the Church and set a precedent for the position of the Christian emperor within the Church and the notion of orthodoxy, Christendom, ecumenical councils, and the state church of the Roman Empire declared by edict in 380. He is revered as a saint and isapostolos in the Eastern Orthodox Church, Oriental Orthodox Church, and various Eastern Catholic Churches for his example as a "Christian monarch."
Constantinople Constantine's foundation gave prestige to the Bishop of Constantinople, who eventually came to be known as the Ecumenical Patriarch, and made it a prime center of Christianity alongside Rome. This contributed to cultural and theological differences between Eastern and Western Christianity eventually leading to the Great Schism that divided Western Catholicism from Eastern Orthodoxy from 1054 onwards. Constantinople is also of great religious importance to Islam, as the conquest of Constantinople is one of the signs of the End time in Islam.