Christian theology

====Trinitarian ecumenical councils====
{{See also|Ecumenical council}}
The Christological controversies came to a head over the persons of the [[Godhead (Christianity)|Godhead]] and their relationship with one another.
Christology was a fundamental concern from the [[First Council of Nicaea]] (325) until the [[Third Council of Constantinople]] (680). In this time period, the Christological views of various groups within the broader Christian community led to accusations of [[Christian heresy|heresy]], and, infrequently, subsequent [[religious persecution]]. In some cases, a sect's unique Christology is its chief distinctive feature, in these cases it is common for the sect to be known by the name given to its Christology.

The decisions made at [[First Council of Nicaea]] and re-ratified at the [[First Council of Constantinople]], after several decades of ongoing controversy during which the work of Athanasius and the [[Cappadocian Fathers]] were influential. The language used was that the one God exists in three persons (Father, Son, and Holy Spirit); in particular it was affirmed that the Son was ''[[homoousios]]'' (of one substance) with the Father. The [[Nicene Creed|Creed of the Nicene Council]] made statements about the full divinity and full humanity of Jesus, thus preparing the way for discussion about how exactly the divine and human come together in the person of Christ (Christology).

Nicaea insisted that Jesus was fully divine and also human. What it did not do was make clear how one person could be both divine and human, and how the divine and human were related within that one person. This led to the Christological controversies of the [[Christianity in the 4th century|4th]] and [[Christianity in the 5th century|5th centuries]] of the Christian era.

The [[Chalcedonian Creed]] did not put an end to all Christological debate, but it did clarify the terms used and became a point of reference for all other Christologies. Most of the major branches of Christianity—[[Catholicism]], [[Eastern Orthodoxy]], [[Anglicanism]], [[Lutheranism]], and [[Calvinism|Reformed]]—subscribe to the Chalcedonian Christological formulation, while many branches of Eastern Christianity—[[Syriac Orthodox Church|Syrian Orthodoxy]], [[Assyrian Church of the East|Assyrian Church]], [[Coptic Orthodoxy]], [[Ethiopian Orthodox]]y, and [[Armenian Apostolic Church|Armenian Apostolicism]]—reject it.