Bede's Ecclesiastical History of England, ed. by A.M. Sellar, , at sacred-texts.com
ABOUT this time, Theodore being informed that the faith of the Church at Constantinople was much perplexed by the heresy of Eutyches, and desiring that the Churches of the English, over which he presided, should remain free from all such taint, convened an assembly of venerable bishops and many learned men, and diligently inquired into the faith of each. He found them all of one mind in the Catholic faith, and this he caused to be committed to writing by the authority of the synod as a memorial, and for the instruction of succeeding generations; the beginning of which document is as follows:
"In the name of our Lord and Saviour Jesus Christ, under the rule of our most pious lords, Egfrid, king of of the Northumbrians, in the tenth year of his reign, the seventeenth of September, the eighth indiction; Ethelred, king of the Mercians, in the sixth year of his reign; Aldwulf king of the East Angles, in the seventeenth year ofhis reign; and Hlothere, king of Kent, in the seventh year of his reign, Theodore, by the grace of God, archbishop of the island of Britain, and of the city of Canterbury, being president, and the other venerable bishops of the island of Britain sitting with him, the holy Gospels being laid before them, at the place which, in the Saxon tongue, is called Haethfelth,we conferred together, and set forth the right and orthodox faith, as our Lord Jesus Christ in the flesh delivered the same to His disciples, who beheld His Presence and heard His words, and as it is delivered by the creed of the holy fathers, and by all holy and universal synods in general, and by the consent of all approved doctors of the Catholic Church. We, therefore, following them, in piety and orthodoxy, and professing accordance with their divinely inspired doctrine, do believe agreeably to it, and with the holy fathers confess the Father, and Son, and Holy Ghost, to be properly and truly a Trinity consubstantial in Unity, and Unity in Trinity, that is, one God in three Subsistences or consubstantial persons, of equal glory and honour."
And after much more of the same sort, appertaining to the confession of the right faith, this holy synod added to its document, "We acknowledge the five holy and general councils of the blessed fathers acceptable to God; that is, of the 318 assembled at Nicaea, against the most impious Anus and his tenets; and at ConstantinopIe, of 150, against the madness of Macedonius and Eudoxius, and their tenets; and at Ephesus, for the first time, of 200, against the most wicked Nestorius, and his tenets; and at Chalcedon, of 630, against Eutyches and Nestorius, and their tenets; and again, at Constantinople, in a fifth council, in the time of Justinian the younger,against Theodorus, and the epistles of Theodoret and Ibas, and their tenets in opposition to Cyril." And again a little lower, "the synod held in the city of Rome, in the time of the blessed Pope Martin,in the eighth indiction, and in the ninth year of the most pious Emperor Constantine,we also acknowledge. And we glorify our Lord Jesus Christ, as they glorified Him, neither adding aught nor taking away; anathematizing with hearts and lips those whom they anathematized, and receiving those whom they received; glorifying God the Father, Who is without beginning, and His only-begotten Son, begotten of the Father before the worlds, and the Holy Ghost proceeding ineffably from the Father and the Son, even as those holy Apostles, prophets, and doctors, whom we have above-mentioned, did declare. And all we, who, with Archbishop Theodore, have thus set forth the Catholic faith, thereto subscribe."