05 — Chalcedon (451)
The Fourth Ecumenical Council, convened by Marcian at Chalcedon in 451, defined that Christ is one person “in two natures, without confusion, without change, without division, without separation” — against Eutyches’ Monophysitism — drawing on Cyril, the Formula of Reunion, and the Tome of Pope Leo. Its Definition is the charter of Orthodox Christology; its aftermath was the enduring separation of the Non-Chalcedonian (Oriental Orthodox) Churches.
Tradition: Pan-Orthodox
Chalcedon is the hinge of Christological history. It rejected the “robber council” of Ephesus 449, deposed Dioscorus, and defined the union of Christ’s two natures in one person with a precision that has governed Orthodox and Western Christology ever since. But its terminology — “in two natures” — was rejected by those who held Cyril’s “one incarnate nature,” and the result was a schism, never healed, between the Chalcedonian Churches and the Oriental Orthodox. This section treats the controversy and the Tome, then the Definition, the separation, and the modern dialogues — the Christological-terminology question handled scrupulously from both sides, without polemic against the Non-Chalcedonians.
Navigation
| File | Description |
|---|---|
| the-controversy-and-the-tome-of-leo.md | Eutyches and Monophysitism; the Latrocinium of Ephesus 449; the Tome of Leo and how it reached the council. |
| the-definition-and-the-non-chalcedonians.md | The “in two natures” Definition; canon 28; the Oriental Orthodox separation; the terminology question both-sides; the modern dialogues and Agreed Statements. |
See Also
- Chalcedon and the Non-Chalcedonian Schism — full compendium — the deep expansion of this section: the road from Ephesus 431 and the Twelve Anathemas through the latrocinium of 449 and the Tome; the sessions of 451, the deposition of Dioscorus and the drafting of the Definition; the Horos quoted exactly and expounded; the Henotikon, Severus of Antioch, Jacob Baradaeus and the parallel hierarchies; Justinian and the Fifth Council; Sts. Sophronius, Maximus and John of Damascus; the terminological question (“Monophysite” / “Miaphysite” / “non-Chalcedonian”) settled at length; and the Chambésy Agreed Statements with the divided Orthodox reception reported both-sides
- St. Leo the Great — author of the Tome
- St. Cyril of Alexandria — whose Christology both sides claim
- Ephesus (431) — the Formula of Reunion that Chalcedon built on
- Orthodoxy: The Seven Ecumenical Councils — the hub essay’s note on the Non-Chalcedonians