Eastern Orthodox Church

=== Early schisms ===

There are the "[[Nestorianism|Nestorian]]" churches resulted from the reaction of the [[Council of Ephesus]] (431), which are the earliest surviving Eastern Christian churches that keep the faith of only the first two ecumenical councils, i.e., the [[First Council of Nicaea]] (325) and the [[First Council of Constantinople]] (381) as legitimate. "Nestorian" is an outsider's term for a tradition that predated the influence of [[Nestorius]], the origin of which might lie in certain sections of the [[School of Antioch]] or via Nestorius' teachers [[Theodore of Mopsuestia]] or [[Diodore of Tarsus]]. The modern incarnation of the "[[Nestorian Church]]" is commonly referred to as "the Assyrian Church" or fully as the [[Assyrian Church of the East]].

The church in Egypt ([[Patriarchate of Alexandria]]) split into two groups following the [[Council of Chalcedon]] (451), over a dispute about the relation between the divine and human natures of [[Jesus]]. Eventually this led to each group [[Anathema#Religious usage|anathematising]] the other. Those that remained in communion with the other patriarchs (by accepting the Council of Chalcedon) are known today as the [[Greek Orthodox Church of Alexandria]], where the adjective "Greek" refers to their ties to the Greek-speaking culture of the Byzantine Empire.

Those who disagreed with the findings of the Council of Chalcedon were the majority in Egypt. Today they are known as the [[Coptic Orthodox Church]], having maintained a separate patriarchate. The Coptic Orthodox Church is currently the largest Christian church in Egypt and in the whole Middle East. There was also a similar, albeit smaller scale, split in [[Syria]] ([[Patriarchate of Antioch]]), which resulted in the separation of the [[Syriac Orthodox Church]] from the [[Greek Orthodox Church of Antioch|Byzantine Patriarchate of Antioch]].

Those who disagreed with the Council of Chalcedon are sometimes called "[[Oriental Orthodoxy|Oriental Orthodox]]" to distinguish them from the "[[Eastern Orthodox]]", who accepted the Council of Chalcedon. Oriental Orthodox are also sometimes referred to as "non-Chalcedonians", or "anti-Chalcedonians". The Oriental Orthodox Church denies that it is monophysite and prefers the term "[[miaphysite]]", to denote the "united" nature of Jesus (two natures united into one) consistent with Cyril's theology: "The term union&nbsp;... signifies the concurrence in one reality of those things which are understood to be united" and "the Word who is ineffably united with it in a manner beyond all description" ([[Cyril of Alexandria]], ''On the Unity of Christ''). This is also defined in the [[Coptic Orthodox Church|Coptic]] liturgy, where it is mentioned "He made it [his humanity] one with his divinity without mingling, without confusion and without alteration", and "His divinity parted not from his humanity for a single moment nor a twinkling of an eye."<ref>{{Cite web|title=Image 219 of The Divine Liturgies of Saints Basil, Gregory, and Cyril|url=https://www.loc.gov/resource/ihas.200155823.0/?sp=219|access-date=4 December 2021|website=Library of Congress}}</ref> They do not accept the teachings of [[Eutyches]], or [[Eutychianism]].<ref>{{Cite web|url=https://www.copticchurch.net/synaxarium/1_7.html#1|last=St Mark's Coptic Orthodox Church, Jersey City, NJ.|title=Tout 7 : Lives of Saints : Synaxarium|access-date=8 December 2023}}</ref><ref>{{Cite web|url=https://st-takla.org/books/en/pope-shenouda-iii/nature-of-christ/eutychianism.html|last=St Takla Haymanaut Coptic Orthodox|title=The Heresy of Eutyches (Eutychianism) – Nature of Christ|access-date=8 December 2023}}</ref> Both the Eastern Orthodox and Oriental Orthodox churches formally believe themselves to be the continuation of the true church.