Council of Seleucia-Ctesiphon

Yazdegerd I adopted a policy of engagement with the Roman Emperor in Constantinople and with the Christian minority in his own empire.

The archbishop of Seleucia-Ctesiphon, the capital city, who is referred to in the acts of the council as the Grand Metropolitan, was to hold authority throughout the Church and for that reason was called (probably only from a later date) the Catholicos.

In order of precedence, the six interior provinces were: The council marked a major milestone in the history of the Church of the East and of Christianity in Asia in general.

The synod also declared its adherence to the decisions of the First Council of Nicaea and adopted a form of the Nicene Creed.

On the other hand, some scholars claim that the second represents the original text of the Seleucia-Ctesiphon Council, and that the words "who is from the Father and the Son" in the second recension are the earliest example of the Filioque clause.