The Seven Ecumenical Councils are the great gatherings, between the fourth and eighth centuries, at which the whole Church came together to confess the apostolic faith against the errors that threatened it. They did not invent doctrine; they named what had always been believed, drawing clear words around the mystery so that it could be guarded and handed on.
Each council answered a real crisis. Nicaea (325) confessed the Son as “of one essence with the Father”; Constantinople (381) completed the Creed and confessed the Spirit; Ephesus (431) named the Virgin Theotokos, God-bearer; Chalcedon (451) confessed Christ one Person in two natures; the fifth and sixth councils clarified His two wills and natures further; and the seventh, Nicaea II (787), confessed the veneration of the holy icons.
The councils are received not as a distant authority but as the living voice of the Church, the same faith spoken in the words each age needed. To hold the faith of the Seven Councils is to hold what has been believed, in the words of St Vincent, “everywhere, always, and by all.”