The Robber Council

By Thomas V. Mirus ( bio - articles - email ) | Oct 01, 2026 | In Lives of the Popes

Previous installment

One of the most consequential events of Pope St. Leo the Great’s reign was the Council of Chalcedon. This council defined the Church’s doctrine of the Incarnation with a precision still accepted not only by Catholics but also by the Orthodox, Lutherans, Anglicans, Calvinists, and many other Christians.

The manner in which the definition came about is of great importance for debates over papal authority. In addition, Chalcedon had important ecclesio-political ramifications for relations between Rome and Constantinople (and thereby much of the Christian East).

And the refusal of a minority of Christians to accept Chalcedon created a schism that has lasted for over 1,500 years—represented to this day by the Oriental Orthodox churches and the Assyrian Church of the East.

In this installment we will look at the events leading up to the Council of Chalcedon, most notably the so-called “Robber Council” of Ephesus, before we look at Chalcedon itself next time.

There were three chief players in the Eastern drama leading up to the Council of Chalcedon. The doctrinal controversy was driven by Eutyches, a monk in Constantinople, whose nephew was chamberlain to the emperor and thus in a position to influence imperial policy. Taking his side was Bishop Dioscorus of Alexandria, formerly deacon of the late St. Cyril; Dioscorus was probably motivated as much by rivalry against Constantinople as by doctrine. Against them was St. Flavian, bishop of Constantinople.

For a deeper examination of the doctrinal issues, you can listen to the Way of the Fathers episode on the heresy of Eutyches, monophysitism. But I will give a brief summary here.

The party of Eutyches claimed to be following the doctrine of St. Cyril of Alexandria. They accused the theologians of Antioch of holding that there were two persons (physes) in Christ; however, the word physis at this point was understood by a great many theologians to mean nature, not person. From this dispute over words was born the monophysite position held by the Alexandrians.

According to Eutyches, Christ had two natures before the Incarnation, but only one nature afterward. He said that the Incarnate Word had a real human body but not a human soul; the Divine intellect and will took the place that a created human soul would have in a normal man.

Eutyches believed he was fighting Nestorianism, which had excessively separated Christ’s divine and human natures. He even wrote to Pope Leo claiming that Nestorianism was proliferating and asking the pope to suppress it; Leo responded with appreciation for Eutyches’s zeal but said he needed more evidence before he could act.

At a synod led by St. Flavian of Constantinople in 448, Eutyches was forbidden to exercise his priesthood and excommunicated as a heretic. He appealed to Rome with the support of the Eastern Emperor Theodosius, while Bishop Dioscorus of Alexandria held his own synod annulling Flavian’s judgment against Eutyches. But Flavian sent a report of the events to Rome, and Leo, feeling he now had enough information for a decision, confirmed the condemnation of Eutyches in early 449.

But St. Leo did not merely confirm the act of the bishop of Constantinople. In a letter to St. Flavian, he himself authoritatively declared “that which the Catholic Church universally believes and teaches about the mystery of the Incarnation of our Lord.” This letter was the famous Tome of Leo, explaining in profound but clear and concise terms the relation between the divine and human natures of Christ. Despite its name, the Tome (or Letter 28) is actually quite short, worth taking the time to read in full (or listen to the 25-minute recording on Catholic Culture Audiobooks). But here is an excerpt:

He who is true God is also true man; there is no falsity in this union, wherein the lowliness of man and the greatness of the divinity are mutually united. Just as God is not changed by His show of mercy, so the man is not changed by being swallowed up in majesty. Each aspect performs its own acts in co-operation with the other; that is, the Word doing what is proper to the Word, the flesh pursuing what pertains to the flesh. The first of these is ablaze with the miraculous, the other is overpowered by injuries. And just as the Word does not give up any of His equality in the Father’s glory, so also the flesh does not abandon the nature of our species.

...

Although in the Lord Jesus Christ there is one person, of God and man, it is only from one of these sources that contempt comes to both in common and from the other source that glory comes to both in common. From us He has a humanity less than the Father; from the Father, a divinity equal to the Father’s. Because, then, of this union of personality (to be understood of both natures) “the Son of man”, as we read, came down from heaven when the “Son of God” assumed flesh from that Virgin through whom He was born. And again, the “Son of God” is said to have been crucified and buried, although this did not pertain to His divinity as such, in which the Only-begotten is co-eternal and consubstantial with the Father; but He endured this in the weakness of His human nature. Hence, too, we all profess in the Creed that the only-begotten “Son of God” was crucified and buried, according to that statement of the Apostle: “For had they known it, they never would have crucified the Lord of glory.”

…

For to have possessed one of these without the other was of no value for salvation; it was equally dangerous to believe that the Lord Jesus Christ was either God only without man, or man only without God.

Influenced by the friends of Eutyches, Emperor Theodosius called for a general council to be held at Ephesus that year to review Flavian’s verdict against the monophysite monastic. Pope Leo was invited to attend, but he declined, in part because there was no precedent for a pope attending an ecumenical council in person. Leo instead sent three legates to attend the council on his behalf, but not without making it known that he thought the council unnecessary since Flavian’s decision had been justified.

The pope also wrote a letter to the council making it clear that he expected it to submit to the Tome. The emperor, Leo wrote, “has paid such deference to the Divine institutions as to apply to the authority of the Apostolic See for a proper settlement: as if he wished it to be declared by the most blessed Peter himself. …But he who both rejects the blessed Peter’s confession, and gainsays Christ’s gospel, is far removed from union with this building.”

As far as Leo was concerned, the purpose of the Ephesian council was not to deliberate on a doctrinal question—that had already been settled by Peter—but to agree with the decision of Rome and then to apply it to the concrete circumstances by healing those led astray by heresy, and by punishing the guilty or remitting his punishment if he repented. For of course, Leo hoped that Eutyches might still be moved to recant his position.

But instead, things went badly wrong—so badly that Leo would remark that the Second Council of Ephesus had made “not a judgment, but a robbery”—and so it would forever after be called the Latrocinium, the Robber Council of Ephesus. The council never gave orthodoxy a chance, would not even permit the papal legates to read the Tome of Leo aloud. And since the emperor did not allow any bishops who had condemned Eutyches to vote, the council naturally voted for his vindication.

Dioscorus, presiding over the council, said that Flavian and other bishops who opposed Eutyches ought to be deposed. In the ensuing outcry, St. Flavian tried to cling to the altar for sanctuary, but soldiers came in and dragged him off to prison. Under this military pressure, a large number of the bishops condemned Flavian. Sentenced to exile, St. Flavian died of his injuries on the road three days later—but not without first having written an appeal to the pope, in which he expressed his conviction that Rome had the authority to totally nullify the acts of the council:

When I began to appeal to the throne of the Apostolic see of Peter, the prince of the Apostles, and to the whole sacred synod which is obedient to your holiness, at once a crowd of soldiers surrounded me and barred the way when I wished to take refuge at the holy altar, as I desired, and tried to drag me out of the church. Then amid the utmost tumult I barely succeeded in reaching a certain part of the church, and there hid myself with my companions, not without being watched, however, to prevent my reporting to you all the wrongs which have been done me.

Therefore I beseech Your Holiness not to permit these things to be treated with indifference…but to rise up first on behalf of the cause of our orthodox faith, now destroyed by unlawful acts. …Further issue an authoritative instruction…so that a like faith may everywhere be preached, by the assembly of a united synod of the fathers, both eastern and western. Thus the laws of the fathers may prevail and all that has been done amiss be rendered null and void: bring healing to this ghastly wound.

This appeal was only able to reach Leo because one of his legates at the council, Hilary, had escaped from under guard and fled through the wilderness, leaving all his baggage behind but bringing St. Flavian’s letter back to Rome with him. It is a fittingly heroic introduction for the man who would succeed Leo as pope.