The Council of Chalcedon (451)
The Second Session Continued: The Bishops Acclaim Cyril’s Letters
When these letters, Cyril’s letter to Nestorius and his letter to John of Antioch, had been read, the most reverend bishops cried out: “We all believe this! Pope Leo believes this! Anathema to anyone who divides, and to anyone who confuses! This is the faith of Archbishop Leo! Leo believes this! Leo and Anatolius believe this! We all believe this! As Cyril, so all of us believe! Eternal be the memory of Cyril! As the letters of Cyril teach, so is our mind; so has our faith been; so is our faith! This is the mind of Archbishop Leo; so he believes; so he has written!”
The most glorious judges and the great senate said: “Let the letter of the most worthy Leo, archbishop of Old Rome, the imperial city, also be read.” Beronician, the most devout clerk of the sacred consistory, read from a book handed to him by Aetius, archdeacon of the holy church of Constantinople. He read the encyclical, or synodical, letter of the most holy Archbishop Leo, written to Flavian, archbishop of Constantinople.