Eastern and Oriental Orthodox: What’s the Difference?

Part 2 – Where and Why the Split Happened

You may have heard that the Eastern and Oriental Orthodox Churches aren’t in full communion. But why? The division goes back to a major event in Church history: the Council of Chalcedon in 451 AD.

What Happened at Chalcedon?

The Council of Chalcedon was the fourth ecumenical council called by the Church. Its goal was to clarify who Jesus Christ is—specifically, how His divine and human natures exist in one person.

The council declared that Jesus is “in two natures”, one divine and one human, united in one person, “without confusion, change, division, or separation.”

Why the Oriental Orthodox Church Didn’t Accept Chalcedon

The Oriental Orthodox Church rejected this wording—not because we deny Christ’s humanity or divinity, but because the phrase “in two natures” seemed to separate Christ too much after the Incarnation.

We followed St. Cyril of Alexandria, who taught that Jesus is “one incarnate nature of God the Word”. In our tradition, we call this Miaphysitism—meaning that the divine and human natures of Christ were united completely and perfectly in one nature, one Person.

We believed the Chalcedonian definition, while trying to be precise, departed from the language of St. Cyril and created unnecessary confusion.

The Result

This disagreement caused a division:

• Churches that accepted Chalcedon became what we now call the Eastern Orthodox and Roman Catholic Churches.

• Churches that rejected Chalcedon and followed St. Cyril became the Oriental Orthodox Churches—including the Coptic, Armenian, Syriac, Ethiopian, Eritrean, and Malankara (Indian) Orthodox Churches.

  
  

Why This Still Matters

Understanding this history helps us see that the split was not about who believed in Jesus, but how to describe what we all believed. That’s why today, many theologians on both sides are working together to restore unity, recognizing that much of the division may have been about language, not faith.