Council_of_Chalcedon The Council of Chalcedon is believed to have been the fourth ecumenical council of the Christian churches of the time. It was held from 8 October to 1 November 451 at Chalcedon (a city of Bithynia in Asia Minor), today the district of Kadıköy on the Asian side of the Bosphorus, incorporated into the city of Istanbul.In 325, the first ecumenical council (First Council of Nicaea) verified through Scripture that Christ was God, "consubstantial" with the Father, against Arius's contention that he was a created being.