The term Oriental Orthodox refers to the churches of Eastern Christian traditions that keep the faith of only the first three Ecumenical Councils of the Orthodox Church—the councils of Nicea I, Constantinople I and Ephesus. The Oriental Orthodox churches rejected the dogmatic definitions of the Council of Chalcedon (A.D. 451). Thus, despite potentially confusing nomenclature, Oriental Orthodox churches are distinct from the churches that collectively are referred to as Eastern Orthodoxy.