Defined Christ as one person in two natures, divine and human, without confusion, change, division or separation — and split the East in doing it.
- Where
- Chalcedon — Kadıköy, Istanbul, Turkey
- Convoked by
- The emperor Marcian, by an edict of 17 May 451 summoning the council for 1 September
- Pope
- Leo I, whose Tome to Flavian the council received as the voice of Peter; he had opposed holding a council at all, and was represented by legates
- Emperor
- Marcian, present with the empress Pulcheria at the sixth session
- Sat
- Opened 8 October 451; the Definition was agreed at the fifth session and solemnly promulgated at the sixth
- Sessions
- Held in the church of St. Euphemia at Chalcedon, across the Bosporus from Constantinople, so the emperor could reach it and the bishops could not be mobbed
- Bishops present
- The largest council of antiquity. Leo speaks of 600 bishops, another letter of 500; modern estimates cluster between 350 and 520
What it faced
Ephesus had defined that Christ is one person. The next question came fast: one person in how many natures? Eutyches, an elderly and revered archimandrite of Constantinople, gave an answer that sounded like loyalty to Cyril — before the union there were two natures, after it, one. The humanity was taken up into the divinity as a drop of honey into the sea.
Flavian of Constantinople condemned him in 448. Eutyches appealed, and in 449 a second council at Ephesus — Dioscorus of Alexandria presiding, imperial soldiers at the doors — reinstated him, deposed Flavian, and refused to let Leo's letter be read. Flavian died shortly after, of injuries received there by most accounts. Leo called the assembly not a council but a latrocinium, a robbery, and the name has stuck to it ever since.
Theodosius II died in a riding accident in 450, and his sister Pulcheria and her new husband Marcian reversed the policy at once. The council that met at Chalcedon a year later had to do two things: undo the Robber Council, and find words for the mystery that neither divided Christ as Nestorius had nor absorbed his humanity as Eutyches did.
What it defined
- ✠That Christ is one and the same Son, acknowledged in two natures, divine and human, and that the four adverbs govern how: without confusion, without change, without division, without separation.
- ✠That the difference of the natures is not taken away by the union; each keeps its own properties, and both come together in one person and one hypostasis.
- ✠That Christ is consubstantial with the Father in his divinity and consubstantial with us in his humanity — like us in all things but sin.
- ✠That Mary is rightly called Theotokos, God-bearer, as regards his humanity — reaffirming Ephesus.
- ✠Twenty-seven disciplinary canons, chiefly on the ordering of bishops, monasteries and appeals.
In its own words
“…one and the same Christ, Son, Lord, only-begotten, acknowledged in two natures which undergo no confusion, no change, no division, no separation; at no point was the difference between the natures taken away through the union, but rather the property of both natures is preserved and comes together into a single person and a single subsistent being; he is not parted or divided into two persons, but is one and the same only-begotten Son, God, Word, Lord Jesus Christ.”
“So, following the saintly fathers, we all with one voice teach the confession of one and the same Son, our Lord Jesus Christ: the same perfect in divinity and perfect in humanity, the same truly God and truly man, of a rational soul and a body; consubstantial with the Father as regards his divinity, and the same consubstantial with us as regards his humanity; like us in all respects except for sin.”
Its canons
The disciplinary rules it made — law, not doctrine, and most of them long since changed.
- Canon 4Monks are placed under the authority of the local bishop and may not wander or found houses at will.
- Canon 6No one is to be ordained without a title — absolute ordinations, to no particular church, are void.
- Canon 9 and 17Appeals may be carried to the exarch of the diocese or to the see of Constantinople — a clause the East and West later read very differently.
- Canon 15A deaconess may not be ordained under forty years of age.
- Canon 28Grants Constantinople equal privileges with Rome and second place after it, as the city of the emperor and the senate. Passed at a late session in the legates' absence; they protested at once and Leo refused to confirm it.
- ✕It did not divide Christ into two persons. That was Nestorius's error, and the Definition explicitly forbids it: 'not parted or divided into two persons, but one and the same only-begotten Son.'
- ✕It did not condemn Cyril. Chalcedon received Cyril's letters as orthodox and understood itself to be interpreting him, not correcting him. Constantinople II in 553 said so again, at length, precisely to make the point.
- ✕Its twenty-eighth canon was not received. Passed at a session the papal legates were not attending, protested by them the next day, and refused confirmation by Leo, it is not part of the council's authority in Catholic law — though the Byzantine Church acted on it for a thousand years.
- ✕It did not settle the East. It broke it — the first lasting division in Christian history, and one which the intervening councils and centuries never healed.
What people think it did
The Oriental Orthodox are monophysites who believe Christ's humanity was swallowed up in his divinity.
What happened: They anathematise Eutyches, who did teach that, and always have. Their position — miaphysitism — is that the divinity and the humanity are united in one nature without mixture, confusion or alteration, which is materially what Chalcedon means by one person in two natures. The joint declarations of 1973 and 1984 say as much in the plainest terms available to both sides.
Canon 28 proves that Rome's primacy was only a matter of the city's political importance, and that the East never accepted a papal claim.
What happened: Canon 28 does argue exactly that about Constantinople's rank — and that is precisely why Rome rejected it, since Rome's claim rested on Peter rather than on the senate. What the same council did accept is instructive: when Leo's Tome was read, the acts record the fathers crying out 'Peter has spoken through Leo.' Both facts belong in an honest account, and the tension between them is real.
What followed
Egypt, much of Syria and Armenia refused the Definition, not because they were Eutychians — they condemned Eutyches too — but because 'in two natures' sounded to them like the division Ephesus had forbidden. They kept Cyril's formula: one incarnate nature of the Word, understood as a single united nature and not a blend. The right name for that position is miaphysite, and calling it monophysitism, as the West did for fifteen centuries, misdescribes it.
The result is the Oriental Orthodox communion — Coptic, Syriac, Armenian, Ethiopian, Eritrean, Malankara — some sixty million Christians today, separated from Rome and Constantinople since 451.
The modern verdict is that the split was largely about words. On 10 May 1973 Paul VI and the Coptic pope Shenouda III signed a common declaration confessing one faith in Christ, 'perfect God with respect to His Divinity, perfect man with respect to His humanity'; on 23 June 1984 John Paul II and the Syriac patriarch Ignatius Zakka I Iwas declared that the divergences were of terminology and culture rather than of substance. The formal separation remains; the charge of heresy, on both sides, has effectively been withdrawn.
Follow it further
Sources
- Council of Chalcedon — Definition and canons (English)
- Common Declaration of Paul VI and Shenouda III (1973)
- Common Declaration of John Paul II and Zakka I Iwas (1984)
Every date, figure and quotation on this page was checked against the conciliar text or a published translation before it was written, and independently re-checked by three separate passes over dates, quotations and theology. Where the sources disagree — attendance figures above all — the page gives the range rather than choosing.