The Nestorian bishops at their synod at the Council of Ephesus declared him a heretic, labelling him as a "monster, born and educated for the destruction of the church".

Yet the 1969 Catholic Calendar revision moved it to 27 June, considered to be the day of the saint's death, as celebrated by the Coptic Orthodox Church.

[12] The prior year, Theophilus had been summoned by the emperor to Constantinople to apologize before a synod, over which Chrysostom would preside, on account of several charges which were brought against him by certain Egyptian monks.

[14] Theophilus arrived at Constantinople with twenty-nine of his suffragan bishops, and conferring with those opposed to the Archbishop, drafted a long list of largely unfounded accusations against Chrysostom,[15] who refused to recognize the legality of a synod in which his open enemies were judges.

[1] Thus, Cyril followed his uncle in a position that had become powerful and influential, rivalling that of the prefect in a time of turmoil and frequently violent conflict between the cosmopolitan city's pagan, Jewish, and Christian inhabitants.

[17] Tension between the parties increased when in 415, Orestes published an edict that outlined new regulations regarding mime shows and dancing exhibitions in the city, which attracted large crowds and were commonly prone to civil disorder of varying degrees.

When Christians responded to what they were led to believe was the burning down of their church, "the Jews immediately fell upon and slew them" by using rings to recognize one another in the dark and killing everyone else in sight.

[21] Nonetheless, with Cyril's banishment of the Jews, however many, "Orestes [...] was filled with great indignation at these transactions, and was excessively grieved that a city of such magnitude should have been suddenly bereft of so large a portion of its population.

[23][24] The Prefect Orestes enjoyed the political backing of Hypatia, an astronomer, philosopher and mathematician who had considerable moral authority in the city of Alexandria, and who had extensive influence.

Indeed, many students from wealthy and influential families came to Alexandria purposely to study privately with Hypatia, and many of these later attained high posts in government and the Church.

Modern historians think that Orestes had cultivated his relationship with Hypatia to strengthen a bond with the pagan community of Alexandria, as he had done with the Jewish one, in order to better manage the tumultuous political life of the Egyptian capital.

[38] Socrates Scholasticus unequivocally condemns the actions of the mob, declaring, "Surely nothing can be farther from the spirit of Christianity than the allowance of massacres, fights, and transactions of that sort.

"[26][36][39] Neoplatonist historian Damascius (c. 458 – c. 538) was "anxious to exploit the scandal of Hypatia's death", and attributed responsibility for her murder to Bishop Cyril and his Christian followers.

"[44] After the murder, a deputation of citizens went to Constantinople to petition the Emperor for an investigation so as to prevent such horrors in the future and to put down the disorderly Parabalani, however they urged for the Patriarch to be allowed to remain in the city (Orestes wanted him banished).

[39] Indeed, the investigation resulted in the emperors Honorius and Theodosius II issuing an edict in autumn of 416, which attempted to remove the parabalani from Cyril's power and instead place them under the authority of Orestes.

However, when John of Antioch and the other pro-Nestorius bishops finally reached Ephesus, they assembled their own Council, condemned Cyril for heresy, deposed him from his see, and labelled him as a "monster, born and educated for the destruction of the church".

Cyril regarded the embodiment of God in the person of Jesus Christ to be so mystically powerful that it spread out from the body of the God-man into the rest of the race, to reconstitute human nature into a graced and deified condition of the saints, one that promised immortality and transfiguration to believers.

Cyril affirmed that the Holy Trinity consists of a singular divine nature, essence, and being (ousia) in three distinct aspects, instantiations, or subsistencies of being (hypostases).

He taught of "μία φύσις τοῦ θεοῦ λόγου σεσαρκωμένη", meaning "one physis of the Word of God made flesh".

The divine Logos was really present in the flesh and in the world—not merely bestowed upon, semantically affixed to, or morally associated with the man Jesus, as the adoptionists and, he believed, Nestorius had taught.

Cyril of Alexandria became noted in Church history because of his spirited fight for the title "Theotokos[53]" during the First Council of Ephesus (431), establishing the ecclesiastically settled basis for all subsequent mariological developments.

[56] Following an epistolary exchange with the increasingly unpopular archbishop of Constantinople, in 430 Cyril wrote his famous 12 Anathemas in which anyone who refused to call Mary Theotokos was condemned.

[57] It is the foremost expression of Cyril's devotion to Mary, and is one of the first historical attestations of the salutation Χαῖρε ("Hail") being used to invoke the Virgin, a practice later standardised in Byzantine homiletics and hymnography such as the sermons of Chrysippus and Basil of Selecucia, and the Akathist hymn.

Mary, who is credited with calling the council fathers together, embodies for Cyril the paradoxes of orthodox Christology, "container of the uncontained" and "the place for the infinite", among other lauded descriptions.

"[54] Wessell notes that in Homily V delivered at the council, Cyril argued that Nestorius' refusal to acknowledge God's incarnate birth from Mary was a blasphemy against Christ.

[60] At the same time, the close relationship between Christological and Mariological formulations going back to the Cappadocian Fathers created a climate wherein intellectual argumentation over disputed theology overlapped with blossoming lay piety.

When the Council of Ephesus convened under Cyril's presidency it did so in the newly constructed Church of Mary,[61] a venue that contributed to the devotional matrix of the debates.

Whereas in the past scholars have often argued that Marian piety and theology only developed in the wake of the conciliar decrees, Shoemaker considers this to be refuted by the picture emerging from liturgical and archaeological evidence.

The marvel strikes me with awe!’" Such sentiments served to further distinguish what Cyril believed to be orthodox theology from that which Nestorius taught, characterising the latter as subversive to both church and empire.

As "scepter of orthodoxy", Mary became the standard of Christological fidelity in Cyril's theology; Nestorius's denial of "Theotokos" became the identifiable sign of his impugning of the divinity of Jesus.