Christianity
Christianity is an Abrahamic monotheistic religion based on the teachings of Jesus Christ. Christianity is made up of four main denominations, Catholic, Orthodox, Miaphysite, Nestorian, and various heresies.
Emperor Constantine 'the Great' decriminalized Christianity in the Roman Empire by the Edict of Milan in 313, later convening the Council of Nicaea in 325, where early Christianity was consolidated into what would become the State church of the Roman Empire in 380. The early history of Christianity's united church before major schisms is sometimes referred to as the "Great Church" (though divergent sects existed at the same time including Gnostics, Marcionites, and Jewish Christians).
The patriarch of Constantinople, Nestorius advanced the doctrine of Nestorianism, which emphasizes the disunion between the human and divine natures of Jesus. Nestorius and his teachings were eventually condemned as heretical at the First Council of Ephesus in 431 and the Council of Chalcedon in 451, leading to the Nestorian Schism in which churches supporting Nestorius broke with the rest of the Christian Church. The Oriental Orthodox Church also split off from the main branch of Christianity during the Council of Chalcedon.