What are the differences between the Oriental Orthodox and Eastern Orthodox churches?

By CopticBot.ai (Coptic Space Inc.) · Last reviewed 2026-10-10

The differences between the Oriental Orthodox (Non-Chalcedonian) and Eastern Orthodox (Chalcedonian) churches are primarily rooted in Christology, history, and the acceptance of Ecumenical Councils. While both families share ancient liturgical forms and a rejection of the Roman Papacy, the theological divide that occurred in the 5th century remains the defining boundary.

1. The Council of Chalcedon (451 AD)

The most significant difference is the acceptance or rejection of the Council of Chalcedon.

• Oriental Orthodox: We reject this council. We hold that it betrayed the teachings of St. Cyril of Alexandria and moved toward the heresy of Nestorianism by dividing Christ into "two natures" after the union.
• Eastern Orthodox: They accept Chalcedon as the Fourth Ecumenical Council. They believe that Christ exists "in two natures" (Divine and Human), which are unconfused but distinct.

2. Christology (The Nature of Christ)

The theological disagreement centers on how the Divinity and Humanity of Christ relate to one another.

• Oriental Orthodox (Miaphysitism): We believe in "One Nature of the Incarnate Word of God." This is the formula of St. Cyril of Alexandria: Mia physis tou Theou Logou sesarkomene. We teach that the Divinity and Humanity were united in a real, perfect, and natural union without mingling, without confusion, without alteration, and without division.
• Eastern Orthodox (Dyophysitism): They teach that Christ has "Two Natures" (Divine and Human) after the Incarnation. While they also say these natures are united without division, we maintain that speaking of "two" natures inherently implies a division that contradicts the perfect union.

3. Number of Ecumenical Councils

• Oriental Orthodox: We recognize only the first three Ecumenical Councils: Nicaea (325 AD), Constantinople (381 AD), and Ephesus (431 AD). These councils established the Creed and the dogma of the Theotokos.
• Eastern Orthodox: They recognize seven Ecumenical Councils, including Chalcedon and three subsequent councils that addressed issues like the will of Christ and the use of icons.

4. Heretics and Saints

Because of the schism, certain individuals are viewed differently:

• Leo of Rome: The Eastern Orthodox venerate Pope Leo I, whose "Tome" was used at Chalcedon. We consider his Tome to be heretical because it divided the actions of Christ between His two natures.
• Dioscorus of Alexandria: We venerate St. Dioscorus as a champion of Orthodoxy who was unjustly deposed at Chalcedon for defending the Cyrillian faith. The Eastern Orthodox consider him a heretic.
• Severus of Antioch: He is a great theologian of our faith; however, he is anathematized by the Eastern Orthodox.

5. Liturgical and Cultural Differences

• Liturgical Standard: The Eastern Orthodox are almost entirely unified under the Byzantine Rite (the Liturgies of St. John Chrysostom and St. Basil). The Oriental Orthodox are a collection of diverse rites (Coptic, West Syrian, Armenian, Ethiopic).
• The Trisagion: In the Coptic Church, we add "Who was crucified for us" to the Trisagion, applying the hymn to the Incarnate Son. The Eastern Orthodox reject this addition, as they apply the hymn to the Holy Trinity.

Summary

While modern dialogues have shown that both sides essentially seek to protect the same truth—that Christ is fully God and fully Man—the Coptic Orthodox Church remains firm that the language of Chalcedon was a dangerous innovation. We are the True Orthodox because we have never deviated from the Cyrillian understanding of the unified nature of our Lord Jesus Christ.