Council of Chalcedon.

The Council of Chalcedon, the Fourth Ecumenical Council of the early Christian Church, was the culmination of the debate concerning whether, during the Incarnation of Jesus Christ, he was human, divine, a mixture of each, or fully each at the same time. This debate was a result of the First Ecumenical Council in Nicaea in 325 c.e. At Nicaea, not far from Chalcedon, the council decided that Christ was both complete God and complete man but did not clarify how that could be possible. The Nicene Creed condemned Arianism, the teaching of Arius in Alexandria that Christ was created by God the Father out of nothing and was therefore neither God nor man. The Nicene Creed was reaffirmed by the Second Ecumenical Council in Constantinople in 381 c.e.