The Copts consistently repudiate the Western identification of Alexandrine Christianity with the Eutycheanism which originated in Constantinople and which they have always regarded as a flagrant heresy since it declared the complete absorption of Christ's manhood in his single divine nature whereas the Copts clearly upheld the doctrine of the two natures, divine and human - mystically united in one without confusion, corruption or change. As a strictly traditional church, its religious leaders have sought biblical justification for this interpretation of the Nicean Creed and the Cyriliian formula, but meanwhile have restricted the substance of their variance to interpretation. Those who can read the Coptic sources both in Coptic and in Arabic, rather than study their doctrinal outlook through secondary works by members of the opposite camp (i.e. the Western Churches) are left wondering whether political and ecclesiastical authority was not behind the unnatural exaggeration of existing differences between the two professions....That the East, or more precisely, the Alexandrine Fathers of the Coptic Church, had led the way in the first three crucial ecumenical councils, seems to be a foregone conclusion which needs no elaboration. That a fourth meeting, at Ephesus, should again be dominated by the Coptic element appeared to strike a note of alarm in the imperial cities of Rome and Constantinople. The subsequent fury of the West over the second Council of Ephesus was demonstrated in its rather impulsive description of it as a "robber council".
Followers of the Council believe its most important achievement was to issue the Chalcedonian Definition, stating that Jesus is "perfect both in deity and in humanness; this selfsame one is also actually God and actually man." The council's judgments and definitions regarding the divine marked a significant turning point in the Christological debates.
The Council of Chalcedon was convened by Emperor Marcian, with the reluctant approval of Pope Leo the Great, to set aside the 449 Second Council of Ephesus which was named the "Latrocinium" or "Robber Council" by Pope Leo. The Council of Chalcedon issued the Chalcedonian Definition, which repudiated the notion of a single nature in Christ, and declared that he has two natures in one person and hypostasis. It also insisted on the completeness of his two natures: Godhead and manhood. The council also issued 27 disciplinary canons governing church administration and authority. In a further decree, later known as canon 28, the bishops declared that the See of Constantinople (New Rome) had the same patriarchal status as the See of Rome.