The Council of Chalcedon

Historical Theology

Historical Setting

Ephesus had secured the unity of Christ’s person against Nestorius, but in correcting one error the church soon faced its opposite. If Nestorius had seemed to divide Christ into two, some among Cyril’s heirs now pressed the unity so far that they confused the natures into one. The pendulum had swung, and the church needed to mark the boundary on the other side.

The crisis came to a head in the figure of Eutyches, an aged and influential monk of Constantinople. In zeal for the unity of Christ he taught that after the incarnation there is but “one nature” — the divine nature having, as it were, absorbed or overwhelmed the human. This teaching, monophysitism (from monos, one, and physis, nature), threatened the reality of Christ’s humanity. A council at Ephesus in 449, dominated by Eutyches’s partisans and conducted with such violence that Pope Leo branded it the “Robber Synod,” wrongfully vindicated him. Two years later a new emperor convened a fresh and fuller council to set matters right.

What Was at Stake

The reality of Christ’s humanity, and with it the reality of our salvation, was at stake. If the human nature is swallowed up by the divine, then Christ is not truly one of us; he has not assumed our nature, and what he has not assumed he has not healed. The Mediator must be true man as well as true God, or he cannot stand in our place and reconcile us to the Father.

Equally at stake was the church’s ability to confess the mystery of Christ in language that excluded both errors at once — both the division of Nestorius and the confusion of Eutyches. The church needed a definition that would fence the truth on every side.

Key Players

Eutyches, the monk whose overzealous defense of Christ’s unity led him to deny the abiding integrity of the two natures.

Pope Leo the Great, bishop of Rome, whose Tome — a letter to Flavian of Constantinople — set out with luminous clarity the Western doctrine of two natures in one person, each nature retaining its own properties and operations.

Flavian of Constantinople, who opposed Eutyches and suffered for it at the Robber Synod.

The Emperor Marcian and Empress Pulcheria, who convened the council. The assembled bishops, more than five hundred, the largest council of the ancient church.

The Outcome

In 451 the Council of Chalcedon, the fourth ecumenical council, met and produced the Chalcedonian Definition. Receiving Leo’s Tome with the famous acclamation “Peter has spoken through Leo,” and honoring Cyril’s teaching on the unity of the person, the council confessed one Christ in two natures, divine and human, united in one person and subsistence. The natures are joined, says the Definition,

without confusion, without change, without division, without separation.

These four adverbs are the church’s enduring fence. “Without confusion” and “without change” exclude Eutyches: the natures are not mixed or altered, and the humanity is not absorbed. “Without division” and “without separation” exclude Nestorius: the natures are not split into two persons. One and the same Christ is fully God and fully man, the two natures concurring in one person.

Scriptural Grounding

Scripture presents the one Christ in whom dwells the fullness of deity bodily:

For in him the whole fullness of deity dwells bodily. (Col. 2:9)

He is true man, sharing our flesh and blood:

he himself likewise partook of the same things … he had to be made like his brothers in every respect. (Heb. 2:14, 17)

Yet without sin (Heb. 4:15). He is the one Mediator, who is himself man (1 Tim. 2:5) and yet the eternal Son who upholds the universe (Heb. 1:3). The two natures, unconfused and undivided, are everywhere assumed in the gospel narratives.

Doctrinal Significance

Chalcedon is the church’s definitive statement on the person of Christ, and one of the high points of Christian doctrinal history. It does not explain the mystery of the incarnation so much as fence it, marking out the boundaries beyond which lies error and leaving the heart of the mystery to faith and worship. Every later orthodox Christology — Catholic, Orthodox, and Protestant alike — stands within these four adverbs.

The doctrine is not abstract. Only if Christ is truly God and truly man, in one undivided person, can he be our Mediator: as God he has infinite worth and power to save; as man he stands in our place and offers a true human obedience and sacrifice; as one person he unites God and man in himself.

A Reformed Assessment — Wheat and Chaff

This is a high point to receive with profound gratitude. The Reformed churches confess the Chalcedonian Definition without reservation, and the Westminster Confession’s chapter on Christ the Mediator is Chalcedonian to its core:

two whole, perfect, and distinct natures … were inseparably joined together in one person, without conversion, composition, or confusion. (WCF 8.2)

The wheat is the whole loaf. If we glean at all, we note that even here the church did not enthrone the council above Scripture; Chalcedon stands because it confesses what the Word teaches, and the Reformed receive it on that ground (WCF 1.10; 31.4). We also note, with sorrow, that not all the East received Chalcedon; the so-called non-Chalcedonian churches separated, and recent dialogue suggests that part of the breach was over terminology rather than substance. The pursuit of precise language, necessary as it is, carries the risk of division, and the church must hold truth and unity together with care.

Connections

The capstone of the Christological work begun in 02_04 and resting on the Trinitarian foundation of 02_01–02_03. Feeds Christology and the person of Christ the Mediator directly (WCF 8). The two-natures doctrine here grounds later debates over the communication of attributes and the Lord’s Supper between Reformed and Lutheran traditions in the Reformation era.

Lessons for Today

The church’s greatest creeds often guard a mystery rather than dissolve it; humility and adoration belong together with precision. Christ is to be received as Chalcedon confesses him — truly God, truly man, one person — and any teaching that trims either nature trims our salvation. And the costliness of the Chalcedonian settlement, which divided some of the church, should make us prize both doctrinal faithfulness and the unity of Christ’s body.