The Niceno-Constantinopolitan symbol

First Ecumenical Council of Nicea, icon from the late 15th-early 16th century, Ambroveneto Collection, Vicenza

The ban on modifying the Symbol of Niceno-Constantinopolitan faith (to which Philarete refers in the interview) had already been enacted by the first canon of the Council of Constantinople (361) and was repeated with force at the Council of Ephesus (431). Canon 7 of the Council of Ephesus reproposes in full the Niceno-Constantinopolitan profession of faith, defining it «holy and fitting to the whole ecumene». But since «some, though pretending to confess it and adhere to it, badly interpret its true meaning according to their way of seeing and alter the truth, being children of error and perdition», the canon brings together an anthology of quotations from «holy orthodox Fathers to demonstrate the way in which they understood and preached this faith with courage, so that it be also clear that all those who have a righteous and immaculate faith understand it, interpret it and preach it in this way». Relying on the authority of the quoted documents, the canon of the Council «establishes that it is not lawful for anyone to propose, compile or formulate a new faith different from what has been defined by the holy Fathers gathered in Nicea with the Holy Spirit. Those who dare formulate a different faith or propose it to whomever wants to convert to the knowledge of the truth coming from Hellenism or from Judaism or from any heresy, if they be bishops or clerics let them be considered lapsed, the bishops from the episcopate, the clerics from their ecclesiastical dignity; if then they be lay people, let them be anathema».