The Fourth Ecumenical Council took place in Chalcedon in 451 AD, and is also known as the Council of Chalcedon. It ruled that Jesus Christ is "in two natures" in opposition to the doctrine of Monophysitism. The council also issued canons dealing mainly with the organization of the Church. The respective acceptance and rejection of this council led to the break between the Chalcedonian Orthodox (the "Eastern Orthodox Church") and the Non-Chalcedonians (the "Oriental Orthodox Church").