- The Council of Chalcedon was held in 451 CE and was the Fourth of the Ecumenical Councils.
- The Council presided over the second great schism in Christianity after the Schism over Arianism.
Rejection of the Second Council of Ephesus
- The Council of Chalcedon was convened by the Eastern Emperor Marcian, specifically to repudiate the Christological conclusions of the Second Council of Ephesus of 449 CE.
- The Second Council of Ephesus had upheld that Christ had one united Nature (Miaphysis) and that he was a divine human.
- The Council was branded as a ‘Robber Council’, and it was not accepted as one of the Ecumenical Councils.
Monophysitism
- The Council of Chalcedon specifically rejected Monophysitism.
Nestorianism
- The Council of Chalcedon banished Nestorianism to the East.
Confirmation of the Pentarchy
- The Council ratified the Title of Patriarch for the five Archbishops in the Roman Empire. They became known as the Pentarchy or Holy Patriarchates of the Holy Catholic and Apostolic Orthodox Church.
- The Pentarchy was made up of the Patriarchs of Rome, Constantinople, Antioch, Jerusalem and Alexandria.
The Eastern Orthodox Churches split from the West
- The rejection of Monophysitism also caused the separation of the Eastern Orthodox Churches from the West, who did not accept the conclusions of the Council of Chalcedon.
The Eastern Orthodox Churches
- The Coptic Orthodox Church of Alexandria
- The Armenian Apostolic Church
- The Syriac Orthodox Church,
- The Ethiopian Orthodox Tewahedo Church
- The Eritrean Orthodox Tewahedo Church
- The Malankara Syrian Church (Indian Orthodox Church).
Chalcedon, a suburb of Istanbul