Council of Chalcedon
The Council of Chalcedon was a Christian gathering held in 451 that defined Christ as one person in two natures, divine and human.
Chalcedonian Definition: The council’s statement that Christ is one person in two natures, united without confusion, change, division, or separation. This creed gives the council’s central doctrinal formula.
Nestorianism: A label for teachings seen as dividing Christ’s divine and human realities too sharply, associated with Nestorius. Chalcedon rejected division in Christ while retaining a distinction between his natures.
Oriental Orthodox Churches: A family of churches that did not accept the Council of Chalcedon and uphold miaphysite Christology. Their rejection of Chalcedon became a lasting ecclesial division.
Marcian: The Eastern Roman emperor from 450 to 457 who convened the Council of Chalcedon with Empress Pulcheria. His government called the council and enforced its decisions.
Hypostatic union: The Christian doctrine that Christ’s divine and human natures are united in one person. It names the theological problem the council’s definition sought to state precisely.
Council of Ephesus: The ecumenical council held in 431 that condemned Nestorius and affirmed Mary as Theotokos. Chalcedon reaffirmed Ephesus while interpreting its teaching on Christ.
Miaphysitism: The Christological teaching that Christ is one united nature from divinity and humanity, without confusion or change. Its formula differs from Chalcedon’s language of two natures, though both traditions affirm Christ’s full divinity and humanity.
Eastern Orthodox Church: A communion of churches that receives the first seven ecumenical councils, including Chalcedon, as authoritative. Its Christology rests in part on the council’s definition.
Pulcheria: The Eastern Roman empress who helped secure the convening of Chalcedon and supported its settlement. Her influence joined imperial authority to the council’s proceedings.
Theotokos: A Greek title meaning “God-bearer,” used for Mary to affirm the unity of Christ’s person. The council upheld this title as consistent with its Christological definition.