First Council of Nicaea
The Council of Nicaea was historically significant because it was the first effort to come to a consensus in the church through an assembly representing all of Christendom. "It was the first occasion for the development of technical Christology." Further, "Constantine in convoking and presiding over the council signaled a measure of imperial control over the church." With the creation of the Nicene Creed, a precedent was established for subsequent general councils to create a statement of belief and canons which were intended to become guidelines for doctrinal orthodoxy and a source of unity for the whole of Christendom — a momentous event in the history of the Church and subsequent history of Europe.