Birth of Christianity
The earliest followers of Jesus were apocalyptic Jewish Christians. The inclusion of gentiles in the developing early Christian Church caused a schism between Judaism and Jewish Christianity during the first two centuries of the Christian Era. In 313, Emperor Constantine I issued the Edict of Milan legalizing Christian worship. In 380, with the Edict of Thessalonica put forth under Theodosius I, the Roman Empire officially adopted Trinitarian Christianity as its state religion, and Christianity established itself as a predominantly Roman religion in the state church of the Roman Empire. Christological debates about the human and divine nature of Jesus consumed the Christian Church for two centuries, and seven ecumenical councils were called to resolve these debates. Arianism was condemned at the First Council of Nicea (325), which supported the Trinitarian doctrine as expounded in the Nicene Creed.