However the Assyrian Church of the East chooses to characterize its beliefs, it is not Orthodox, nor is there any pretense to being allied to the Orthodox. And, the issue is the 4th EC. If one of the churches you mentioned didn't accept the 3rd EC, then that church is even further from Orthodoxy
Forgive me, but you seem to be confused about what I have and havenot said in the course of this thread. I have not referred to the Assyrian Church of the East as Orthodox, nor have I called for us to engage in full communion with them.
Although they have it should be stressed corrected their Christology, and did so in the sixth century, so it could be said they accept the fourth ecumenical council but not the third, which is obviously a problem. Actually, one reason why the Oriental Orthodox did not agree to Chalcedon was the praise heaped on it by crypto-Nestorians such as Ibas, and indeed Nestorius himself praised it in his somewhat pompous memoirs, the Bazaar of Heraclides, although I regard this praise as either based on ignorance of the actual contents of the council, or senility, or perhaps Nestorius was being disingenuous; I do not regard Nestorius with sympathy, given the very comfortable nature of his exile compared to that of St. John Chrysostom, who was death marched, or the Syriac Orthodox bishops who were imprisoned and murdered (except for Mor Ya’kub Bar Addai), or St. Maximos the Confessor, who had his tongue cut out, and died as a result, especially given that Nestorius reportedly used violence against those people who refused to deny that Our Glorious Lady and Ever Virgin Mary was Theotokos, and accept his misleading, crypto-antidicomarian term Christotokos.
However, regarding the Assyrian Church of the East, they did discard his Christology in favor of a Syriac translation of Chalcedonian Christology by Mar Babai the Great just over 1500 years ago, and as a matter of fact they were in intermittent communion with the Eastern Orthodox during the late first millennium, when they were regarded as “the Persian Church.” And this did not endear us to the Oriental Orthodox, who are, especially in the case of the Coptic Orthodox*, best described as the anti-Nestorian church, which I greatly admire, given that while Eutychian Monophysitism is dead, largely thanks to Coptic efforts to eradicate it in the 5th century, and its own degeneration into Tritheism in the 6th century under John Philoponus (Monophysites such as Eutyches, and their successors such as John Philoponus, were anathematized by the Oriental Orthodox, which disagrees that the human and divine natures of our Lord became merged or that the human nature dissolved into the divine nature, as Eutyches argued), whereas Nestorianism has made a major comeback among Protestants and Restorationist churches; if we were to do a poll I think as many as 20% of the members of CF.com might confess some form of Nestorian belief, because like Nestorius, they refuse to use the term “Theotokos” or to admit that Our Lady gave birth to God, and thus are forced to invent skewed theological systems as a result.
However, as I have indicated, it is not all bad as far as the Assyrian Church of the East is concerned, since they are no longer Christologically Nestorian, and indeed have not been for 1500 years, and their non-Nestorianism was further clarified by certain statements made by Catholicos Mar Dinkha IV in 1975, and what is more, we also now know, although some Eastern and Oriental Orthodox are in denial about this, that St. Isaac the Syrian, who is the last saint to be venerated by all four ancient communions (RC, EO, OO and the Assyrian and Ancient Churches of the East**)/, was a member of the Assyrian Church of the East, and like St. Gregory of Nyssa, and most members of the Assyrian Church of the East in the late first millenium, believed in Apokatastasis, that is to say, that damnation was not permanent. The Assyrian church has since rejected this error.
I suspect you are confusing the Assyrian Church of the East with the Syriac Orthodox Church, since the two have partially overlapping jurisdiction (but not as overlapping as the Syriac Orthodox and the Antiochians), in that the Assyrians and Syriac Orthodox both operate in Iraq and in India. They also both worship using Classical Syriac, but that is also true of the Antiochian Orthodox and the Maronite Catholics (and also the Chaldean Catholics, Syriac Catholic, Syro-Malabar Catholics and Malankara Catholics) who are Chalcedonian. But the similarities end there. The Assyrian church no longer has monasteries or any significant amount of iconography, and the Syriac Orthodox Church has both, in abundance, and also the Assyrians worship using the East Syriac liturgy, whereas the Syriac Orthodox worship using the ancient Antiochene liturgical rite, which is very similiar to the Byzantine liturgy of the Eastern Orthodox, which was primarily derived from Antiochene sources (specifically, the Divine Liturgy of St. John Chrysostom is a minor variation on the ancient Anaphora of the Twelve Apostles; the Syriac Orthodox use both, and that of St. Basil, and also the Anaphora of St. James that many Orthodox churches use on October 23rd, and the Anaphora of St. Cyril, also known as the Divine Liturgy of St. Mark, which is occasionally used by the Greek Orthodox Church of Alexandria, and frequently used by the Coptic Orthodox.
The Syriac Orthodox also overlap much more with the Antiochians, in that the only territory where they operate and the Antiochians have no presence is the Holy Land (there is a Syriac-speaking population in Jerusalem, centered around the Monastery of St. Mark, which is the most likely location of the Cenacle, since the Crusader Church is more likely than not actually built over the Tomb of King David), and the Holy Sepulchre, and in Bethlehem, a similiar community centered around the Syriac Orthodox portion of the Church of the Nativity complex, St. Mary’s Church (the Syriac Orthodox are the only church to have their own private church located immediately next to the Church of the Nativity, although I believe they also use the larger Greco-Armenian church on occasions such as Christmas, as it accommodates more worshippers than their own church, and they do a liturgy with the Coptic Orthodox pilgrims). The Syriac Orthodox overlap with the Antiochians in Lebanon, Syria, Iraq, Eastern Turkey (in the area of Antakya, formerly Antioch) and presumably India, since Antiochian canonical territory is supposed to include all of Asia (although in practice other churches have not respected this, and there are very few Eastern Orthodox in India). Of these churches, only the Assyrians and the Oriental Orthodox Armenian Apostolic Church have any significant presence in Iran (Persia).
*This also applies to their daughter churches the Ethiopian and Eritrean Tewahedo Orthodox (both of which were, as recently as a century ago, part of the Coptic Orthodox Church).
** The Ancient Church of the East separated from the Assyrian Church of the East in the 1960s over two issues: the discovery, by one of the bishops of the Church of the East that the hereditary Patrairchate that then existed was uncanonical; this became a non-issue with the assasination of Catholicos Mar Shimun XXIIII in 1974, who was the last hereditary Catholicos-Patriarch, and also the controversial decision by Mar Shimun XXIII to switch to the Gregorian calendar. However about 14 years ago the two churches announced plans to merge, although this hasn’t happened yet due to the ISIS war in Iraq and Syria and the deaths of Catholicos Mar Dinkha IV and more recently, Mar Addai II, who had been Catholicos of the Ancient Church of the East since it first separated.
