The holy, great, and ecumenical synod, assembled by the grace of God and the command of our most religious and Christian Emperors, Marcian and Valentinan, Augusti, at Chalcedon, the metropolis of the Bithynian Province, in the martyry of the holy and victorious martyr Euphemia, has decreed as follows:
Our Lord and Saviour Jesus Christ, when strengthening the knowledge of the Faith in his disciples, to the end that no one might disagree with his neighbour concerning the doctrines of religion, and that the proclamation of the truth might be set forth equally to all men, said, "My peace I leave with you, my peace I give unto you." But, since the evil one does not desist from sowing tares among the seeds of godliness, but ever invents some new device against the truth; therefore the Lord, providing, as he ever does, for the human race, has raised up this pious, faithful, and zealous Sovereign, and has called together unto him from all parts the chief rulers of the priesthood; so that, the grace of Christ our common Lord inspiring us, we may cast off every plague of falsehood from the sheep of Christ, and feed them with the tender leaves of truth. And this have we done with one unanimous consent, driving away erroneous doctrines and renewing the unerring faith of the Fathers, publishing to all men the Creed of the Three Hundred and Eighteen, and to their number adding, as their peers, the Fathers who have received the same summary of religion. Such are the One Hundred and Fifty holy Fathers who afterwards assembled in the great Constantinople and ratified the same faith. Moreover, observing the order and every form relating to the faith, which was observed by the holy synod formerly held in Ephesus, of which Celestine of Rome and Cyril of Alexandria, of holy memory, were the leaders, we do declare that the exposition of the right and blameless faith made by the Three Hundred and Eighteen holy and blessed Fathers, assembled at Nice in the reign of Constantine of pious memory, shall be pre-eminent: and that those things shall be of force also, which were decreed by the One Hundred and Fifty holy Fathers at Constantinople, for the uprooting of the heresies which had then sprung up, and for the confirmation of the same Catholic and Apostolic Faith of ours.
The Creed of the three hundred and eighteen Fathers at Nice. We believe in one God, etc.
Item, the Creed of the one hundred and fifty holy Fathers who were assembled at Constantinople We believe in one God, etc.
This wise and salutary formula of divine grace sufficed for the perfect knowledge and confirmation of religion; for it teaches the perfect [doctrine] concerning Father, Son, and Holy Ghost, and sets forth the Incarnation of the Lord to them that faithfully receive it. But, forasmuch as persons undertaking to make void the preaching of the truth have through their individual heresies given rise to empty babblings; some of them daring to corrupt the mystery of the Lord's incarnation for us and refusing [to use] the name Mother of God (Theotokos) in reference to the Virgin, while others, bringing in a confusion and mixture, and idly conceiving that the nature of the flesh and of the Godhead is all one, maintaining that the divine Nature of the Only Begotten is, by mixture, capable of suffering; therefore this present holy, great, and ecumenical synod, desiring to exclude every device against the Truth, and teaching that which is unchanged from the beginning, has at the very outset decreed that the faith of the Three Hundred and Eighteen Fathers shall be preserved inviolate. And on account of them that contend against the Holy Ghost, it confirms the doctrine afterwards delivered concerning the substance of the Spirit by the One Hundred and Fifty holy Fathers who assembled in the imperial City; which doctrine they declared unto all men, not as though they were introducing anything that had been lacking in their predecessors, but in order to explain through written documents their faith concerning the Holy Ghost against those who were seeking to destroy his sovereignty. And, on account of those who have taken in hand to corrupt the mystery of the dispensation [i.e. the Incarnation] and who shamelessly pretend that he who was born of the holy Virgin Mary was a mere man, it receives the synodical letters of the Blessed Cyril, Pastor of the Church of Alexandria, addressed to Nestorius and the Easterns, judging them suitable, for the refutation of the frenzied folly of Nestorius, and for the instruction of those who long with holy ardour for a knowledge of the saving symbol. And, for the confirmation of the orthodox doctrines, it has rightly added to these the letter of the President of the great and old Rome, the most blessed and holy Archbishop Leo, which was addressed to Archbishop Flavian of blessed memory, for the removal of the false doctrines of Eutyches, judging them to be agreeable to the confession of the great Peter, and as it were a common pillar against misbelievers. For it opposes those who would rend the mystery of the dispensation into a Duad of Sons; it repels from the sacred assembly those who dare to say that the Godhead of the Only Begotten is capable of suffering; it resists those who imagine a mixture or confusion of the two natures of Christ; it drives away those who fancy his form of a servant is of an heavenly or some substance other than that which was taken of us, and it anathematizes those who foolishly talk of two natures of our Lord before the union, conceiving that after the union there was only one.
Following the holy Fathers we teach with one voice that the Son [of God] and our Lord Jesus Christ is to be confessed as one and the same [Person], that he is perfect in Godhead and perfect in manhood, very God and very man, of a reasonable soul and [human] body consisting, consubstantial with the Father as touching his Godhead, and consubstantial with us as touching his manhood; made in all things like unto us, sin only excepted; begotten of his Father before the worlds according to his Godhead; but in these last days for us men and for our salvation born [into the world] of the Virgin Mary, the Mother of God according to his manhood. This one and the same Jesus Christ, the only-begotten Son [of God] must be confessed to be in two natures, (1) unconfusedly, immutably, indivisibly, inseparably [united], and that without the distinction of natures being taken away by such union, but rather the peculiar property of each nature being preserved and being united in one Person and subsistence, not separated or divided into two persons, but one and the same Son and only-begotten, God the Word, our Lord Jesus Christ, as the Prophets of old time have spoken concerning him, and as the Lord Jesus Christ hath taught us, and as the Creed of the Fathers hath delivered to us.
These things, therefore, having been expressed by us with the greatest accuracy and attention, the holy Ecumenical Synod defines that no one shall be suffered to bring forward a different faith (eteran pistin), nor to write, nor to put together, nor to excogitate, nor to teach it to others. But such as dare either to put together another faith, or to bring forward or to teach or to deliver a different Creed (eteron sumbolon) to as wish to be converted to the knowledge of the truth, from the Gentiles, or Jews or any heresy whatever, if they be Bishops or clerics let them be deposed, the Bishops from the Episcopate, and the clerics from the clergy; but if they be monks or laics: let them be anathematized.
After the reading of the definition, all the most religious Bishops cried out: This is the faith of the fathers: let the metropolitans forthwith subscribe it: let them forthwith, in the presence of the judges, subscribe it: let that which has been well defined have no delay: this is the faith of the Apostles: by this we all stand: thus we all believe.