The Council of Chalcedon was an ecumenical council that took place from October 8 to November 1, 451, at Chalcedon (a city of Bithynia in Asia Minor), today part of the city of Istanbul on the Asian side of the Bosphorus and known as the district of Kadıköy.
It is the fourth of the first seven Ecumenical Councils in Christianity, and is therefore recognized as infallible in its dogmatic definitions by the Roman Catholic and Eastern Orthodox churches. It repudiated the Eutychian doctrine of monophysitism, and set forth the Chalcedonian Creed, which describes the "full humanity and full divinity" of Jesus, the second person of the Holy Trinity. This action thus set aside the findings of the Second Council of Ephesus in 449.