Assyrian Church = Nestorians? Oriental Orthodox = Monophysites?

For me, there is a little confusion surrounding the Assyrian Church of the East and the Oriental Orthodox Christians.

So, basically my original understanding was…

In 431 AD, The Council of Ephesus was established as the third ecumenical council. One of the doctrines condemned by this council was Nestorianism. Nestorians objected to the title of Mary as the “Theotokos” (Mother of God) because of their belief that Jesus’ two natures, human and divine, were completely seperate and that when God came as Jesus, He was either God or man, but never at the same time. The Assyrian Church of the East were Nestorians and thus broke away.

In 451 AD, The Council of Chalcedon was established as the fourth ecumenical council. One of the doctrines condemned by this council was Monophysitism which teaches that Jesus had one nature, a mix of human and divine, rather than two. Certain Eastern bishops held to this doctrine broke away and these became Oriental Orthodoxy. ********

If this is inaccurate, what was the reason why did the Assyrian Church of the East and Oriental Orthodox Christians not accept these councils?

Also, what’s the difference between Miaphysites, Monophysites, and general/mainstream Christian understanding of the nature(s) of Christ?

Monophysites BElieve Jesus Has “Only One” Nature And Miaphysites Believe Jesus Has “One” Nature.

Default Assyrian Church = Nestorians? Oriental Orthodox = Monophysites?

Both can be answered with a simple No. The ACoE is not “Nestorian”, and the OO are not “monophysite”.


The OO absolutely affirm the complete humanity and divinity of Jesus without mixture, separation, or mingling - just like us Chalcedonians and we both reject Eutychianism. It’s my understanding that the ACoE likewise agree with us, but I haven’t read anything from them personally.

So what’s the differences between what these two groups believe and what Ephesian-Chalcedonian Christians believe?

The Oriental Orthodox hold dear the Christology of St. Cyril (Ephesus). So they simply express Christ’s complete-and-indivisible humanity and divinity in terms of “One Incarnate Nature of the Word” rather than “Two Natures in One Hypostatic Union” (two complete natures, human and divine, hypostatically and indivisibly united without change or mingling). While some of them may disagree with our Christological language, we can’t consistently disagree with theirs without, IMO, condemning St. Cyril’s beliefs and Ephesus.

So, differences? Nothing, apart from being from one of two legitimate language traditions used to describe the same Mystery, as the various agreed statements between the OO and the Chalcedonians bear witness to.

And as I said, I don’t know enough about the ACoE to say anything about them with much certainty. IIRC, the Roman Catholic Church has agreed Christological statements with them saying the two churches pretty much agree, but someone else will have to comment here.

Basically a difference in emphasis. (Edit: See neokarny’s more detailed post above.)

This book might help define some of the terms as they were used during the Council itself:

So if it’s just only a matter of semantics, and the Oriental Orthodox are substantively Chalcedonian, why aren’t the Oriental Orthodox in communion with the Eastern Orthodox?

While I understand the Miaphysite position, and their reasons for rejecting Chalcedon, having had the linguistic issues explained to me by a Copt, I have never heard a similar explanation from an Assyrian (due to lack of meeting Assyrians in a religious setting). Those who I’ve met who have an affinity to the Assyrian practice certainly seem to have a Nestorian outlook (one argued the idea of Jesus being “100% man and 100% God”).

I’m curious if anyone can explain the ways in which they differ from Nestorianism, and why they rejected Ephesus. The fact that they and Rome have signed a statement of agreement doesn’t convince me of anything, they have one of those with both us and the OO

In part the issue is administrative, but another very real issue becomes how to deal with Chalcedon and the post-Chalcedonian councils.

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