[5] In his struggle against Nestorius, Cyril explained the union between the divine and human natures of Christ as "inward and real without any division, change, or confusion."

In this letter he praises Dioscorus' modesty and humility, stating: "you do not behold the multitude of your subjects nor the exaltation of your throne, but you see rather human nature, and life's rapid changes, and follow the divine laws whose observance gives us the kingdom of heaven".

[7] Cyril's nephew Athanasius, who C. Haas describes as a "wealthy Alexandrian priest and potential rival" was a fierce critic of Dioscorus.

Immediately after his accession Dioscorus was worried that the influential group of Cyril's relatives would be tempted to sabotage his tenure.

According to the deacon Ischyrion in the third session of the Council of Chalcedon in 451, Dioscorus had laid waste to property, inflicted fines and exile, as well as buying up and selling at a high price the wheat sent by the government to Libya.

In November 448, Flavian, Bishop of Constantinople held a synod regarding a point of discipline connected with the province of Sardis.

Eutyches had been accusing various personages of covert Nestorianism, and at the end of the session of this synod one of those inculpated, Eusebius, Bishop of Dorylaeum, brought the question forward, and proffered a counter charge of heresy against the archimandrite.

[12] Through the influence of the court official Chrysaphius, the godson of Eutyches, in 449, Emperor Theodosius II convened the Second Council of Ephesus.

The council subsequently decided to reinstate Eutyches and to depose Flavian, as well as Eusebius of Dorylaeum, Theoderet of Cyrrus, Ibas of Edessa, and Domnus II of Antioch.

In the spring of 450 at Nicaea, Dioscorus, while on his way to the court, caused ten bishops whom he had brought from Egypt to sign a document excommunicating Pope Leo.

Given they wanted to overturn the results of the council, he notes that Pope Leo I would never have been willing to recognise Anatolius as bishop if Flavian were still alive.

[15] Theophanes the Confessor, writing three centuries after the event, says that Dioscorus personally struck Flavian "both with hands and feet".

But I have quotations from the holy fathers Athanasius, Gregory and Cyril saying in numerous places that one should not speak of two natures after the union".

According to the minutes of the council of Chalcedon, Dioscorus stated: "If Eutyches holds opinions contrary to the doctrines of the church, he deserves not only punishment but hell fire.

Pulcheria is said to have slapped Dioscorus in the face, breaking some of his teeth, and ordered the guards to confine him, which they did pulling his beard hair.

[4][12] Following Dioscorus's deposition and exile, an Alexandrian priest named Proterius was appointed Patriarch in his stead, with the approval of the emperor.

[citation needed] Certain modern theologians (as well as ancient ones like Basil of Seleucia) suggest that both Leo and Dioscorus were orthodox in their agreement with Saint Cyril's Twelve Chapters, even though both have been (and still are) considered heretical by some.

[21] Some commentators like Anatolius and John S. Romanides argue that Dioscorus was not deposed for heresy but for "grave administrative errors" at Ephesus II, among which they mention his restoration of Eutyches, his attack on Flavian, and afterwards, his excommunication of Pope Leo I. Defenders of Dioscorus argue that Eutyches was orthodox at the time of his restoration and only later lapsed into heresy, that Flavian was a Nestorian, and that Pope Leo had supported Nestorianism.

They deny this charge, arguing that they reject both the Monophysitism of Eutyches, whom they consider a heretic, as well as Dyophysitism espoused by the Council of Chalcedon, which they equate with Nestorianism, for a doctrine they term miaphysitism, or that in Jesus Christ, divinity and humanity exist as "one incarnate nature" (physis), as opposed to the Chalcedonian teaching of a divine and a human nature united in the one person (hypostasis) of Jesus Christ, fully God and fully man, a doctrine called the "hypostatic union".

[24] A similar declaration was reached between the Oriental and Eastern Orthodox churches in 1990 in Geneva, in which both agreed in condemnation of the Nestorian and Eutychian "heresies" and in rejection of interpretations of ecumenical councils which do not fully agree with the Horos of the Third Ecumenical Council and the letter (433) of Cyril of Alexandria to John of Antioch.