The Council of Chalcedon concludes. It was the fourth ecumenical council of the Christian Church, at it had convened on October 8, 451 in the city of Chalcedon, Bithynia (modern-day Kadıköy, Istanbul, Turkey).
The council, convoked by the Roman emperor Marcian was attended by over 520 bishops or their representatives. The Council declared Jesus Christ to have two natures—fully divine and fully human in one person. The council also elevated the see of Constantinople to a position of honor, granting it privileges equal to those of Rome and e council explicitly condemned the Eutychian doctrine of monophysitism and also issued canons on church discipline.