An extract on #ig_masterpiece
Another theological dispute in the 5th century occurred over the teachings of Nestorius, the Patriarch of Constantinople who taught that God the Word was not hypostatically joined with human nature, but rather dwelt in the man Jesus. As a consequence of this, he denied the title "Mother of God" (Theotokos) to the Virgin Mary, declaring her instead to be "Mother of Christ" Christotokos.
When reports of this reached the Apostolic Throne of Saint Mark, Pope Saint Cyril I of Alexandria acted quickly to correct this breach with orthodoxy, requesting that Nestorius repent. When he would not, the Synod of Alexandria met in an emergency session and a unanimous agreement was reached. Pope Cyril I of Alexandria, supported by the entire See, sent a letter to Nestorius known as "The Third Epistle of Saint Cyril to Nestorius." This epistle drew heavily on the established Patristic Constitutions and contained the most famous article of Alexandrian Orthodoxy: "The Twelve Anathemas of Saint Cyril." In these anathemas, Cyril excommunicated anyone who followed the teachings of Nestorius. For example, "Anyone who dares to deny the Holy Virgin the title Theotokos is Anathema!" Nestorius however, still would not repent and so this led to the convening of the First Ecumenical Council of Ephesus (431), over which Cyril presided.
The Council confirmed the teachings of Saint Athanasius and confirmed the title of Mary as "Mother of God". It also clearly stated that anyone who separated Christ into two hypostases was anathema, as Cyril had said that there is "One Nature [and One Hypostasis] for God the Word Incarnate" (Mia Physis tou Theou Logou Sesarkmen). Also, the introduction to the creed was formulated as follows:
We magnify you O Mother of the True Light and we glorify you O saint and Mother of God (Theotokos) for you have borne unto us the Saviour of the world. Glory to you O our Master and King: Christ, the pride of the Apostles, the crown of the martyrs, the rejoicing of the righteous, firmness of the churches and the forgiveness of sins. We proclaim the Holy Trinity in One Godhead: we worship Him, we glorify Him, Lord have mercy, Lord have mercy, Lord bless us, Amen. [not dissimilar to the "Axion Estin" Chant still used in Orthodoxy]
The Dean of the Great Catechetical School of Theology of Alexandria.
The Ecumenical (Universal) Judge (Arbitrator) of the Holy Apostolic and Catholic (Universal) Church.
The 13th among the Holy Apostles.
The Pillar and Defender of the Holy, Catholic (Universal), Apostolic Church and of the Orthodox Doctrine.