The main entry's brief mention of christological agreements with the Oriental Orthodox understates how remarkable this achievement is, since it addresses a division, over Chalcedon's christological formula of 451, that had stood as one of Christianity's oldest and most fundamental splits.
The Oriental Orthodox churches, including the Coptic, Syriac, Armenian, Ethiopian and Eritrean Orthodox churches, rejected Chalcedon's definition that Christ exists "in two natures," holding instead a miaphysite christology, that Christ's divine and human natures are united in one nature without confusion or division, a position their critics historically, and inaccurately per most modern scholars, characterized as "monophysite," collapsing his humanity into his divinity. Beginning with academic conversations from the 1960s and continuing through official joint commissions, Orthodox and Oriental Orthodox theologians produced joint christological statements, including agreements in 1989 and 1990, concluding that the two families hold the same christological faith expressed in different technical vocabularies shaped by different Greek and Syriac traditions, and that the historical condemnations rested substantially on terminological misunderstanding rather than genuine doctrinal disagreement.
These agreements have not produced full restored communion, since practical and historical-memory obstacles remain considerable after fifteen centuries of separate development and, in several periods, real persecution between the communities, but the finding itself is treated by ecumenical theologians as one of the most substantive achievements of the modern ecumenical movement, resolving, at the level of theological content, one of Christianity's oldest and most consequential fractures.