From the perspective of one who studies Historical Theology, the Catholic-Orthodox Schism in 1054 is one of the most detrimental events in modern history. No matter what side you view the Schism from, millions of Christians were separated from the True Church. For the 1.329 billion Catholics today, there are 220 million separated Christians with legitimate Apostolic Succession operating outside the authority of the Church, and vice versa for Orthodox Christians. To understand why this break happened, we must go much further back in history than 1054.
Within the early Church, these two Communions were one. It wasn’t until the Council of Ephesus in 431 that the heresies attributed to Nestorius were condemned. Nestorianism created a divide between the two natures of Christ, human and divine. The Nestorians claimed that Our Lady should hold the title Christotokos, the Christ-bearer, and not Theotokos, the God-bearer. Nestorius’ followers were excommunicated, thus creating the Church of the East. Today, the descendants of Nestorian Christianity are within the communions of the Assyrian Church of the East and the Chaldean Syrian Church, the first Churches broken away from the Catholic Church.
20 years later in 451, the Council of Chalcedon was called to combat the heresy of Monophysitism. This heresy was the opposite of the Nestorian heresy of the same century. The Monophysitism heresy, headed by Eutyches, was the belief that Christ was only of one nature, the divine, and that His humanity was so miniscule, “like a drop of honey absorbed by the water of the sea,” that He was a non-compounded union of human and divine within a singular nature. A very similar view to this came about from the excommunicated Church at this time was Miaphysitism. This theology, stemming from Cyril of Alexandria, claimed that Christ was of one physis, meaning nature. The Council defined that Christ is one hypostasis, person, composed of two physeis, or natures. This Church is what we now know as the Oriental Orthodox Churches, the Armenian Church, West Syriac Church, the Coptic Church, and the Ethiopian Church.
These two Churches today only make up for 60 million separated Christians, but the final schism within the Apostolic Church was the separation of Eastern Orthodox Christians in 1054. This schism differs from the previous two in that it was not through one Council decision that the excommunications were served, it was a much longer process. In 1014 all Roman governed Churches had the Filioque clause, the clause that states that the Holy Spirit proceeds from the Father “and the Son,” added into the Nicene Creed. This caused tensions to rise between Rome and Constantinople, the seat of the Eastern Churches. This was because in 431, a Council not attended by the seat of Rome had declared that Constantinople and Rome were equal in authority, but this Canon, Canon 28 of the Council of Ephesus, was rejected and nullified by the Pope. These issues lead to the mutual excommunication between the Pope of Rome and the Patriarch of Constantinople, splitting the Church into the Catholic and Eastern Orthodox Churches.
I write this so that we may understand the history behind these schisms because without understanding the history, we cannot move toward union. We must know the intimacies of these heresies and political fights to be able to avoid these problems and resolve them, allowing the entire Church to come back into unity, the way Christ desires. We must continue to pray for unity within Apostolic Christianity and the return home of the schismatics.
Lord Jesus Christ, have mercy on me a sinner.