The First Council of Nicaea was the first ecumenical council of the Church. Most significantly, it resulted in the first uniform Christian doctrine, called the Nicene Creed. With the creation of the creed, a precedent was established for subsequent local and regional councils of Bishops (Synods) to create statements of belief and canons of doctrinal orthodoxy—the intent being to define unity of beliefs for the whole of Christendom.
they also banned certain Gospels, made early Christian leaders into Witches and other fun stuff.
Have at it.