Answer:
The council of Chalcedon.
Explanation:
The Council of Chalcedon, also known as the Fourth Ecumenical Council was a meeting of Christian leaders in the Roman Empire which established the mature expression of Christian faith known as Chalcedonian Orthodoxy. Held from October 8 to November 1, 451 at Chalcedon, it attempted to resolve the issue of how to express the concept of Christ as being both fully human and fully divine.
