Monophysitism

 also known as Monophysitism is a part of Christianity, who rejected the reforms of the Council of Chalcedon in 451 out of fear it was too similar to Nestorianism, thus was considered a heretic by the other Orthodox Christian. He is an older form of Christianity.

Armenia followed him because he was too busy fighting Sassanid in 451 to go to the council meeting. Ethiopia and a few other countries follow him too. Nubia followed it until the 16th century. It also has a major presence in Egypt under Copt and Eritrea but also has a tiny presence in the northern Middle East & India.

Orthodox two largest communions are Oriental Orthodox and Eastern Orthodox.