Eastern Orthodoxy vs. Oriental Orthodoxy: Who Preserved the Apostolic Faith?

Two families of ancient churches both call themselves Orthodox. One is the Eastern Orthodox Church: Constantinople, Antioch, Alexandria, Jerusalem, Russia, Greece, Serbia and the rest, which confess seven ecumenical councils. The other is the Oriental Orthodox family: the Coptic, Syriac, Armenian, Ethiopian, Eritrean and Indian (Malankara) churches, which are in communion with one another and receive the first three councils but not the fourth, Chalcedon (451).¹ For about fifteen centuries each regarded the other as having departed from the apostolic faith about how Christ is both God and man.

The site already has an introduction to what Chalcedon defined about Christ. This article goes further, reading both sides in their own words and then the modern dialogue, before asking who preserved the apostolic faith.

In brief

Both families confess one Lord Jesus Christ, the eternal Word, fully divine and fully human, born of the Theotokos, and both reject Nestorius and Eutyches. The quarrel after 451 was largely about wording: Chalcedon confessed Christ "in two natures," while Cyril had also spoken of "one incarnate nature of the Word." Each side heard the other's formula as heresy. Severus of Antioch shows that the non-Chalcedonians used "nature" for the concrete individual, not the essence, and that they anathematized Eutyches. Eastern Orthodoxy itself accepted Cyril's formula, rightly understood, in 553. Between 1964 and 1993 theologians of both families, at the end officially appointed, concluded that the two "have always loyally maintained the same authentic Orthodox Christological faith." What still divides them is chiefly the authority of the four later councils, the anathemas on each other's saints, and the reception of the agreements, which some Eastern Orthodox, notably Mount Athos, reject.

Thesis: The primary sources suggest that both families preserved the apostolic faith in Christ under different vocabularies, so the remaining dispute is chiefly about councils, anathemas and church authority, and those questions have not been settled by either family.

The primary historical evidence

Cyril of Alexandria spoke two ways

Everything begins with St Cyril of Alexandria, the father both families revere. Against Nestorius, Cyril insisted that the one born of Mary is the eternal Word himself. Yet in his second letter to Nestorius, which was read at the Council of Ephesus in 431, he could speak of "the two natures being brought together in a true union," adding that "the difference of the natures is not taken away by the union."² In 433 he made peace with John of Antioch by accepting a confession that said "there became a union of two natures," and that some sayings of the Gospels are taken "as pertaining to the one person" while others are divided "as to the two natures."³

After 433 Bishop Succensus asked him whether one ought to admit two natures, and Cyril explained himself. "After the union has occurred," he wrote, "we do not divide the natures from one another," but "we say that there is One Son, and as the holy Fathers have stated: One Incarnate Nature of The Word." He would admit two united natures only "theoretically speaking," as the mind distinguishes them.⁴ So Cyril left both vocabularies to his heirs: "out of two natures" and "one incarnate nature" on the one hand, a union "of two natures" distinguished in thought on the other.

One detail matters for honesty. Cyril presented the "one nature" formula as a saying of the holy Fathers, and Severus later named St Athanasius as its source. The New Catholic Encyclopedia notes that it is actually found in a work of Apollinaris of Laodicea that circulated among the works of Athanasius, and that Cyril, believing it Athanasian, gave it an orthodox meaning Apollinaris had not intended.⁵ Its meaning in Cyril is orthodox, but neither side can treat it as an Athanasian password.

What Chalcedon actually said and did

The Council of Chalcedon met in 451 after the disastrous second council of Ephesus (449), which had restored Eutyches and which Pope Leo, writing to the empress Pulcheria in July 451, called a meeting "not of judges but of robbers," which is why it is remembered as the Robber Council.⁶ Its definition confesses "one and the same" Son, "perfect in Godhead and perfect in manhood," consubstantial with the Father and with us, and continues: he "must be confessed to be in two natures, unconfusedly, immutably, indivisibly, inseparably [united]," the property of each nature preserved and "united in one Person and subsistence, not separated or divided into two persons."⁷ The same definition formally "receives the synodical letters of the Blessed Cyril." Chalcedon understood itself as Cyrillian.

The acts also show where the trouble lay. During the first session, as the minutes of the earlier proceedings against Eutyches were read, Dioscorus of Alexandria interjected: "I receive the of two; the two I do not receive."⁸ He accepted "out of two natures," not "in two natures." When a draft definition was put forward in the fifth session, the papal legates threatened to leave, and the imperial commissioners put the choice bluntly: "Dioscorus acknowledged that he accepted the expression of two natures, but not that there were two natures." Which would the bishops follow, Leo or Dioscorus? The commissioners then directed that the definition state "that there are two natures in Christ," and a committee produced the text now known as the Definition.⁹

Dioscorus was deposed, but the sentence gives as reasons "your disregard of the divine canons," his "disobedience to this holy and ecumenical synod," the "other crimes" he was found guilty of, and his refusal to come when summoned three times. The "other crimes" were charges arising from his presidency of the council of 449, where he had restored Eutyches, so the Chalcedonian case against him was not only procedural. {{strong: The deposition notice of Chalcedon does not condemn Dioscorus for heresy.}}¹⁰ The modern translators of the acts, Richard Price and Michael Gaddis, concluded (as quoted by Gregory Tucker) that "the later characterization of Dioscorus as a Eutychian heretic is not securely based on the proceedings of Chalcedon."¹¹

Leo's Tome and why it alarmed Alexandria

Leo's letter to Flavian of Constantinople (449), the Tome, was acclaimed at Chalcedon with the cry "Leo and Cyril taught the same thing."¹² Its most disputed sentence reads: "For each form does what is proper to it with the co-operation of the other; that is the Word performing what appertains to the Word, and the flesh carrying out what appertains to the flesh."¹³ Leo meant the one Christ acting in two ways, but to Alexandrian ears two "forms" each doing their own work sounded like two acting subjects, the Nestorian danger Cyril had fought.

Severus of Antioch in his own words

Severus (c. 465 to 538), patriarch of Antioch from 512 until his expulsion in 518, became the theologian of the non-Chalcedonian churches.¹⁴ His letters, which survive mostly in Syriac, answer the charge of "monophysitism" directly.

First, Severus explains his vocabulary. "Nature" can mean a common essence, as when we call mankind one nature, or an individual, as when we speak of "one nature of Paul." When he says "one incarnate nature of God the Word," he writes, "we use 'nature' in place of 'individual designation', denoting the one hypostasis of the Word himself."¹⁵ By "one nature" he means what Chalcedon means by "one hypostasis."

Second, he rejects Eutyches. Asked why Eutyches is anathematized, Severus calls him "the man of ill name and impious." Dioscorus had received him in 449, Severus explains, because he presented a document "which contained a right confession of faith," but afterwards Eutyches "seems again to have 'returned to his vomit'."¹⁶

Third, his objection to Chalcedon is to "two natures after the union." Speaking of two natures "as if divided into a duality," he warns, makes "the notion of difference" reach "to the extent of division."¹⁷ He quotes Leo's Tome as dividing "the one and only Christ into two natures" and insists that "the one Word incarnate" performed both the divine and the human acts.¹⁸

Severus was condemned at Constantinople in 536. The Orthodox scholar John Behr notes that his opponents' charges were contradictory, since the imperial edict that confirmed the sentence accused him of "both Nestorianism and Eutychianism," and that the reversal followed the arrival in Constantinople of Pope Agapetus, who had come to seek Justinian's help against the Goths. His books were burned and he was banished.¹⁹

How Eastern Orthodoxy itself received Cyril's formula

The Second Council of Constantinople (553), the fifth ecumenical council for the Orthodox, anathematized anyone who uses "the expression of two natures" or "the one nature made flesh of God the Word" without understanding them "as the holy Fathers have taught," that is, as a hypostatic union without confusion.²⁰ The Orthodox councils thus explicitly allowed Cyril's "one nature" language, rightly understood. The same council condemned the writings of Theodoret of Cyrus against Cyril's twelve anathemas.²¹

The Third Council of Constantinople (680 to 681) added a further point: Christ has "two natural wills and two natural operations indivisibly, inconvertibly, inseparably, inconfusedly." Its definition calls the one-will teaching "an heresy similar to the mad and wicked doctrine of the impious Apollinaris, Severus, and Themistius."²² This is the hardest test for reconciliation, because the charge against Severus here concerns wills and operations, the theology of St Maximus the Confessor, not only the word "nature."

The modern dialogue

Four unofficial consultations of theologians were followed by an official Joint Commission appointed by the churches.²³

Meeting	Status	Main result
Aarhus, Denmark, 1964	Unofficial	"On the essence of the Christological dogma we found ourselves in full agreement."
Bristol, England, 1967	Unofficial	The four adverbs of Chalcedon belong to both; discussion of wills and energies
Geneva, 1970; Addis Ababa, 1971	Unofficial	Named the remaining obstacles: councils, anathemas, jurisdiction
Chambésy, Switzerland, 1985	Official	Joint Commission begins work
Anba Bishoy Monastery, Egypt, 1989	Official	First Agreed Statement on Christology
Chambésy, 1990	Official	Second Agreed Statement and recommendations to the churches
Chambésy, 1993	Official	Proposals for lifting the anathemas

At Aarhus the participants wrote that "the acceptance or non-acceptance of the Council of Chalcedon does not entail the acceptance of either heresy," and that Chalcedon is "best understood in the light of the later Council of Constantinople (553)."²⁴ At Bristol they put the difference memorably: "Those who speak in terms of 'two' do not thereby divide or separate. Those who speak in terms of 'one' do not thereby commingle or confuse." They also faced the seventh-century question. All agreed that "the human will is neither absorbed nor suppressed by the divine will," and judged that speaking of one divine-human will and energy "does not appear therefore to be incompatible" with the council of 680 to 681.²⁵

The official statements went further. The First Agreed Statement (1989) built on Cyril's formula and confessed that each nature, divine and human, is united "including natural will and natural energy."²⁶ The Second Agreed Statement (1990) said that both families condemn Eutyches and "the crypto-Nestorianism of Theodoret of Cyrus"; that the Orthodox accept the Oriental Orthodox use of "one nature of the incarnate Logos" ("The Orthodox also use this terminology"); and that the Oriental Orthodox accept the Orthodox "two-natures formula, since they acknowledge that the distinction is 'in thought alone'."²⁷ Its conclusion was strong: {{moderate: "both families have always loyally maintained the same authentic Orthodox Christological faith, and the unbroken continuity of the apostolic tradition, though they have used Christological terms in different ways."}} It recommended lifting the anathemas on both sides, and in 1993 the Commission proposed that this be done "unanimously and simultaneously by the Heads of all the Churches of both sides," with full communion following at once.²⁸

What still divides the two families

The four later councils

The 1990 statement does not say that the Oriental Orthodox accept councils four to seven. It says that the Orthodox regard the agreed points as the teaching of those councils, "while the Oriental Orthodox consider this statement of the Orthodox as their interpretation," and respond to it "positively." On icons, the Oriental Orthodox agreed that the teaching of the seventh council is "in basic agreement" with their own ancient practice.²⁹ Already in 1970 the Eastern Orthodox participants had stressed that for them the seven councils form "a single indivisible complex."³⁰ For Eastern Orthodox Christians the ecumenical councils are not optional, as the site's article on how the Church recognizes an ecumenical council explains.

The anathemas and the liturgical texts

Each family has condemned saints the other venerates. The 1970 consultation named Leo on one side and Dioscorus and Severus on the other.³¹ These condemnations live on in worship. Gregory Tucker's study of the Byzantine service for the Fathers of Chalcedon counts fourteen heretics named in it, of whom only three (Dioscorus, Severus and Jacob Baradaeus) are contested in the dialogue. He argues that the hymns often lump these men together with Eutyches, attributing to them views they did not hold, and that a revision would touch relatively few texts.³² The Athonite fathers answered that such a revision would leave the services "mutilated," since these texts are, in their view, "basic elements of Orthodoxy."³³

Reception and authority

The sharpest opposition came from within Eastern Orthodoxy. In 1995 the Sacred Community of Mount Athos issued a memorandum denouncing the Joint Commission. It objected that the Commission treated "Dioscorus, Jacob, Severus, etc." as "not heretical but Orthodox in their thinking," that lifting an anathema of an ecumenical council is "alien to the sound mind of the Church," and that Maximus, Sophronius, John of Damascus and other fathers had judged non-Chalcedonian Christology heretical. It reported that a committee of the Church of Greece had advised in 1994 that the Oriental Orthodox must accept the definition of Chalcedon and the four later councils "without interpretive statements," and that the Russian Church's synod had judged the 1990 statement not "a final text."³³ The Russian Church later opened its own talks after its Bishops' Council of 1997 asked for "the Christological formulations" of the 1990 document to be clarified.³⁴

Scholars raise a different objection. Fr John Behr, sympathetic to Severus, records that Fr John Meyendorff "presented Severus as being a forerunner of monoenergism," and that Aloys Grillmeier wrote, "Without a doubt Severus already contributes to the monoenergist, monothelite controversy of the seventh century." Behr argues that this misreads Severus as the old charge of "monophysitism" did, since Severus affirmed a human will and energy in Christ while insisting that one and the same Christ acts.³⁵ {{debated: Whether Severus's teaching on Christ's will and activity is fully compatible with the council of 680 to 681 is still argued among scholars.}} From the other side, Tucker notes that the scholar Hans van Loon has argued that Cyril's own two-nature language is "not just notional, but real," which would weaken the dialogue's reliance on Cyril's "one nature" formula as the common key.³⁶

Where things stand now

Some churches acted locally. In 1991 the Orthodox Patriarchate of Antioch and the Syriac Orthodox Patriarchate, both of which claim the apostolic see of Antioch, signed a synodal letter affirming "the total and mutual respect of the spirituality, heritage and Holy Fathers of both Churches" and allowing a sole priest of either church in a locality to serve the faithful of both, "including the Divine Liturgy."³⁷ In 2001 the Greek Orthodox and Coptic Orthodox Patriarchates of Alexandria agreed to recognize each other's marriages, noting that their synods had accepted the agreed statements and recognized each other's baptism, but that "the restoration of full communion is not yet reached."³⁸

Full communion between the two families has not been restored. In May 2025 the heads of the Oriental Orthodox churches of the Middle East reported that a preparatory committee for the two families had met in Egypt in September 2024 and that they "support all efforts aimed at the continuation of this dialogue."³⁹ In November 2025 a conference at Holy Cross School of Theology in Massachusetts, organized by scholars and hierarchs of both families, said the agreed statements "must either bring us to the point of visible unity and sacramental communion, or the churches must speak authoritatively as to why this could not be possible." It also acknowledged "vocal opponents" on Mount Athos and in Eastern Europe.⁴⁰ That conference spoke for its participants, not for the churches.

The Orthodox position

It helps to separate three levels.

• Dogma. The Eastern Orthodox Church confesses the seven ecumenical councils, including Chalcedon's "in two natures" and the two wills and energies of the sixth council. Nothing in the dialogue has changed this, and no pan-Orthodox decision has received the agreed statements. The Creed both families share is the Nicene Creed without the Filioque, and the 1989 statement agrees that the Holy Spirit "proceeds from the Father alone."⁴¹
• Common tradition. Cyril is a father of both families, and the Orthodox councils themselves allow his "one incarnate nature" when it is understood as the fathers taught. Both families venerate the Theotokos and the icons and have a closely similar sacramental and liturgical life, though they are not in communion, as the site's map of Christian traditions shows.
• Theological opinion. Whether the Oriental Orthodox hold the faith of Chalcedon in substance, whether anathemas pronounced by councils can be lifted, and how communion should be restored are matters on which Orthodox bishops and theologians honestly disagree, from Antioch's pastoral generosity to Athos's refusal.

An Orthodox reader can therefore hold, without contradiction, that the councils are true and binding and that those they were aimed at may not hold what they condemned.

The strongest objections

"Chalcedon changed the faith; we kept Cyril's."

This is the Oriental Orthodox case at its strongest. Cyril defended "one incarnate nature" and "out of two"; Chalcedon chose "in two," praised a Tome that speaks of two forms each acting, deposed Dioscorus, and was enforced by imperial power. Severus could say that he, not Chalcedon, spoke as Cyril did. Pope Shenouda III of the Coptic Church wrote that "the Holy Church did not find an expression more reliable, deep and precise" than Cyril's.⁴²

Response: Cyril himself accepted a "union of two natures" in 433, and Chalcedon received his letters by name. Leo's sentence speaks of the co-operation of the other form, not of two persons. The council of 553 accepted Cyril's formula when it is understood as the Fathers taught. Chalcedon guarded something Cyril also held: after the union the humanity remains truly human.

"If the agreement is real, why not unite now?" and its opposite

Some ask why, if the faith is the same, communion is still withheld; others, like the Athonite fathers, ask how a council's anathema can ever be lifted. The Orthodox answer to the first is that communion is restored by whole churches, not commissions; to the second, that councils condemn teachings, and the dialogue claims the persons named did not hold them. Whether that distinction can apply to men a council named is the open question.

"Fifteen centuries of schism over words proves the councils were unnecessary."

Both families answer that the words guarded something real: if Christ is not one subject, God did not become man; if his humanity is not ours, ours is not healed. The site's article on Jesus Christ, true God and true man explains why.

What we can say confidently

• Both families reject Nestorius and Eutyches; Severus called Eutyches "impious" and upheld his anathema.
• Cyril used both "one incarnate nature of the Word" and "union of two natures," and both families claim him.
• Chalcedon's notice of deposition gives canonical, not doctrinal, grounds for removing Dioscorus.
• The Orthodox council of 553 accepted "one nature made flesh of God the Word" when rightly understood.
• The Joint Commission (1989, 1990) concluded that both families hold the same Christological faith, and recommended lifting the anathemas.
• Full communion has not been restored, and the agreed statements have not been received by all the churches.

What remains disputed

• Whether Severus's teaching on Christ's will and activity agrees with the sixth council, or contains an implicit monoenergism.
• Whether Cyril's own thought was more "one nature" or more "two natures" (van Loon's challenge).
• Whether the anathemas of ecumenical councils on named persons can be lifted, and by whom.
• Whether the Oriental Orthodox must formally accept councils four to seven, or only their teaching, before communion.
• How far politics, language and empire caused the original division.

Conclusion

Who preserved the apostolic faith? On the evidence of their own writers, there is a strong case that both families preserved the faith in the incarnate Word that the apostles preached and Nicaea confessed, each guarding it against a different danger. The Eastern Orthodox Church holds, and this site holds, that the seven councils are the Spirit-led voice of the Church, and that their definitions cannot be set aside. Holding that with integrity means reading Dioscorus and Severus as they wrote, not only as later hymns portray them.

For Christians who confess the same Christ and pray the same Creed, the separation is, in the words of the Orthodox co-chairman at Anba Bishoy in 1989, "a bleeding wound in the body of Christ."⁴³ Orthodox Christians can pray for its healing without pretending the questions are answered, and without doubting the councils that taught them to confess Christ rightly. Readers can meet the fathers named here in the Church Fathers Explorer and the overview of what the seven councils decided.

Notes

1. Geevarghese Mar Osthathios, "Oriental Orthodox Churches," Dictionary of the Ecumenical Movement, rev. ed. (WCC and Eerdmans, 2002), as reproduced by the World Council of Churches on oikoumene.org, naming the "six Oriental Orthodox churches" and describing them as "the churches of the first three ecumenical councils."
2. Cyril of Alexandria, Second Letter to Nestorius, in H. R. Percival, ed., The Seven Ecumenical Councils, NPNF2 vol. 14 (1900), Council of Ephesus.
3. Cyril of Alexandria, Letter to John of Antioch (April 433), NPNF2 vol. 14, trans. Percival.
4. Cyril of Alexandria, First Letter to Succensus, sections 6-7, trans. John A. McGuckin, St. Cyril of Alexandria: The Christological Controversy (St Vladimir's Seminary Press, 2004), 352-58, as reproduced on St-Takla.org.
5. F. Chiovaro, "Apollinarianism," New Catholic Encyclopedia, 2nd ed. (via Encyclopedia.com): the formula "is found in Apollinaris' Incarnation of the Word of God, which is frequently interpolated among the works of St. Athanasius."
6. Leo the Great, Letter 95 (to Pulcheria, 20 July 451), section 2, trans. C. L. Feltoe, NPNF2 vol. 12. The meeting is conventionally called the Latrocinium ("Robber Council"); Tucker, 481 n. 34, gives the popular tag "non concilium sed latrocinium."
7. Council of Chalcedon, Definition of Faith, NPNF2 vol. 14, trans. Percival.
8. Council of Chalcedon, Session I, NPNF2 vol. 14.
9. Council of Chalcedon, Session V, NPNF2 vol. 14 (the legates' threat, the commissioners' question and the committee). The wording of the earlier draft is not given in the NPNF excerpts and is not quoted here.
10. Council of Chalcedon, Session III, "The Condemnation Sent by the Holy and Ecumenical Synod to Dioscorus," NPNF2 vol. 14. Percival's summary adds that the bishops voted for deposition "usually on the ground of his refusal to appear when thrice summoned."
11. Tucker, 481-82 (the "other crimes" "of which he was accused as president of the Council of Ephesus of 449"), quoting R. Price and M. Gaddis, The Acts of the Council of Chalcedon (Liverpool University Press, 2005), vol. 1, 34-35. The Price and Gaddis volumes were not opened for this article.
12. Council of Chalcedon, Session II, NPNF2 vol. 14.
13. Leo the Great, Letter 28 (the Tome), 13 June 449, trans. C. L. Feltoe, NPNF2 vol. 12.
14. E. W. Brooks, introduction to A Collection of Letters of Severus of Antioch, Patrologia Orientalis 12.2 (1915): patriarch "from 512 to 518," died "in exile in Egypt in 538"; Behr, 23, gives c. 465-538.
15. Severus, Letter to Maron (513-18, date queried by Brooks), in Brooks, Collection of Letters, letter VI.
16. Severus, Letter to the orthodox brothers in Tyre (513-18), in Brooks, letter XXXII.
17. Severus, Letter to Eleusinius (516-18), in Brooks, letter X.
18. Severus, First Letter to Oecumenius (508-12), in Brooks, letter I.
19. Behr, 24, citing ACO 3 for the edict.
20. Second Council of Constantinople (553), anathema 8, NPNF2 vol. 14, trans. Percival.
21. Second Council of Constantinople, anathema 13, NPNF2 vol. 14.
22. Third Council of Constantinople (680-81), Definition of Faith (Session XVIII), NPNF2 vol. 14.
23. Joint Commission, Communiqué, Chambésy, December 1985, naming "the four unofficial consultations of Aarhus (1964), Bristol (1967), Geneva (1970) and Addis Ababa (1971)"; Proposals for Lifting of Anathemas (1993), section 1, on "our three official meetings which followed on (1985, 1989, 1990)."
24. First Unofficial Consultation, Aarhus, Agreed Statement (1964), as published by the Syriac Orthodox Patriarchate's Department of Syriac Studies.
25. Second Unofficial Consultation, Bristol, Agreed Statement, 29 July 1967, sections 2, 4-5, in Greek Orthodox Theological Review 13.2 (1968), 133-36.
26. Joint Commission, First Agreed Statement, Anba Bishoy Monastery, June 1989.
27. Joint Commission, Second Agreed Statement, Chambésy, September 1990, sections 1-2, 7, as published by the Ecumenical Patriarchate's Permanent Delegation to the WCC.
28. Second Agreed Statement, sections 9-10; Joint Commission, Proposals for Lifting of Anathemas, Chambésy, November 1993, sections 2-3.
29. Second Agreed Statement, section 8.
30. Third Unofficial Consultation, Geneva, August 1970, Summary of Conclusions, section A.
31. Geneva 1970, section B: anathemas "should be discontinued as in the case of Leo, Dioscurus, Severus, and others."
32. Tucker, 476-87.
33. Memorandum of the Sacred Community of Mount Athos concerning the dialogue (1995), sections II, III, IV, IX and XI, as published by the Orthodox Christian Information Center. Tucker, 475, dates it to 1995.
34. Joint Commission for the Relations between the Oriental Orthodox Churches and the Russian Orthodox Church, report of the Moscow meeting, 4-6 September 2001.
35. Behr, 28-35, citing Meyendorff, Christ in Eastern Christian Thought (rev. ed. 1975), 43, and Grillmeier and Hainthaler, Christ in Christian Tradition 2.2 (1995), 149. Neither book was opened for this article.
36. Tucker, 484 n. 38, quoting H. van Loon, The Dyophysite Christology of Cyril of Alexandria (Brill, 2009), 540. Van Loon's book was not opened for this article.
37. Statement of the Orthodox Church of Antioch on the Relations between the Eastern and Syrian Orthodox Churches, Damascus, 12 November 1991, signed by Patriarchs Ignatius IV and Ignatius Zakka I.
38. Pastoral agreement between the Greek Orthodox Patriarchate of Alexandria and the Coptic Orthodox Church, signed 5 April 2001 by Petros VII and Shenouda III (press release of the Patriarchate of Alexandria; text of the agreement as given by OrthodoxWiki).
39. Common Declaration of the fifteenth meeting of the heads of the Oriental Orthodox Churches in the Middle East, Cairo, 17-18 May 2025 (Middle East Council of Churches).
40. "Moving the Dialogue Forward": Report and Conclusions from the Conference on Eastern and Oriental Orthodox Relations, Holy Cross School of Theology, 4-6 November 2025, sections 4 and 6.
41. First Agreed Statement (1989), final paragraph.
42. Pope Shenouda III, The Nature of Christ, chapter 2, "The Orthodox Concept regarding the Nature of Christ" (St-Takla.org edition).
43. Joint Commission, communiqué introducing the First Agreed Statement (1989), quoting Metropolitan Damaskinos of Switzerland, co-chairman (text as reproduced by Trinity College Orthodox School of Theology, Toronto).

Bibliography

Primary sources

• Percival, Henry R., ed. and trans. The Seven Ecumenical Councils. Nicene and Post-Nicene Fathers, Second Series, vol. 14. New York: Scribner's; Buffalo: Christian Literature Publishing, 1900. (Acts and definitions of Ephesus, Chalcedon, Constantinople II and III; Cyril's letters to Nestorius and to John of Antioch.) Online at newadvent.org and ccel.org.
• Cyril of Alexandria. First Letter to Succensus. In John A. McGuckin, St. Cyril of Alexandria: The Christological Controversy: Its History, Theology, and Texts. Crestwood, NY: St Vladimir's Seminary Press, 2004, 352-58.
• Leo the Great. Letter 28 (the Tome). Trans. Charles Lett Feltoe. Nicene and Post-Nicene Fathers, Second Series, vol. 12. Buffalo: Christian Literature Publishing, 1895.
• Severus of Antioch. A Collection of Letters of Severus of Antioch from Numerous Syriac Manuscripts. Ed. and trans. E. W. Brooks. Patrologia Orientalis 12.2. Paris, 1915. Online at tertullian.org.

Orthodox and patristic sources

• Agreed Statement of the First Unofficial Consultation of Eastern and Oriental Orthodox theologians, Aarhus, 1964. Department of Syriac Studies, Syriac Orthodox Patriarchate (dss-syriacpatriarchate.org).
• "Agreed Statement," Bristol, 29 July 1967. Greek Orthodox Theological Review 13.2 (1968): 133-36.
• Summary of Conclusions of the Third Unofficial Consultation, Geneva, 16-21 August 1970. Department of Syriac Studies, Syriac Orthodox Patriarchate.
• Joint Commission of the Theological Dialogue between the Orthodox Church and the Oriental Orthodox Churches. Communiqué (Chambésy, 1985), First Agreed Statement (Anba Bishoy, 1989) and Second Agreed Statement (Chambésy, 1990). Ecumenical Patriarchate Permanent Delegation to the WCC (ecupatria.org); also Trinity College Orthodox School of Theology, Toronto.
• Joint Commission. Proposals for Lifting of Anathemas. Chambésy, 1-6 November 1993. Department of Syriac Studies, Syriac Orthodox Patriarchate.
• Holy Synod of Antioch. Statement of the Orthodox Church of Antioch on the Relations between the Eastern and Syrian Orthodox Churches. Damascus, 12 November 1991. Syriac Orthodox Resources.
• Greek Orthodox Patriarchate of Alexandria and Coptic Orthodox Church. Pastoral Agreement regarding the Sacrament of Matrimony. Cairo, 5 April 2001. Patriarchate of Alexandria press release (reproduced at orthodox.net) and OrthodoxWiki.
• Sacred Community of Mount Athos. "Memorandum Concerning the Dialogue Between the Orthodox and Non-Chalcedonian Churches." 1995. Orthodox Christian Information Center (orthodoxinfo.com).
• Joint Commission for the Relations between the Oriental Orthodox Churches and the Russian Orthodox Church. Report of the second meeting, Moscow, 4-6 September 2001. Department of Syriac Studies, Syriac Orthodox Patriarchate.
• Huffington Ecumenical Institute. "Moving the Dialogue Forward": Report and Conclusions from the Conference on Eastern and Oriental Orthodox Relations. Holy Cross School of Theology, 4-6 November 2025.
• Behr, John. "Severus of Antioch: Eastern and Oriental Orthodox Perspectives." St. Nersess Theological Review 3.1-2 (1998): 23-35.

Other scholarship

• Tucker, Gregory. "Byzantine Hymnography and the Quest for Orthodox Unity: Notes on the Liturgical Commemoration of the Council of Chalcedon, Towards the Reconciliation of 'Eastern' and 'Oriental' Churches." Review of Ecumenical Studies 11.3 (2019): 473-88. DOI 10.2478/ress-2019-0033.
• Chiovaro, F. "Apollinarianism." New Catholic Encyclopedia. 2nd ed. Detroit: Gale, 2003. Via Encyclopedia.com.
• Osthathios, Geevarghese Mar. "Oriental Orthodox Churches." In Dictionary of the Ecumenical Movement, rev. ed. Geneva: WCC; Grand Rapids: Eerdmans, 2002. Reproduced at oikoumene.org.

Sources from the Oriental Orthodox tradition

• Shenouda III, Pope. The Nature of Christ. St-Takla.org edition.
• Heads of the Oriental Orthodox Churches in the Middle East. Common Declaration of the Fifteenth Meeting. Cairo, 17-18 May 2025. Middle East Council of Churches (mecc.org).