The Nestorian Schism was the split between the Byzantine church of the West and the Assyrian church of the East in the 5th century. Nestorius was a student of Theodore of Mopsuestia at the middle School of Antioch before he became Patriarch of Constantinople. He was condemned by Cyril of Alexandria and the First Council of Ephesus (431) for refusing to call the Virgin Mary by the title Theotokos (Mother of God); he instead insisted to refer to her by the title Christokos Mother of Christ. He was further condemned for splitting Christ into two persons, although he clearly denied that accusation (see Nestorianism for detailed information on Nestorius's teachings). The whole affair was complicated by the dubious arguments of Cyril of Alexandria, which soon provoked the Monophysite Schism.