The fifth-century Christological heresy teaching that after the incarnation Christ has only one nature (the divine), the human nature having been absorbed into, transformed by, or commingled with the divine. The principal teacher of the heresy was Eutyches, archimandrite of a monastery near Constantinople, who taught a strong reaction against the Nestorian over-emphasis on the distinction of the natures. Eutyches's formulation — after the union, one nature — was condemned at the Council of Chalcedon (451), which adopted the orthodox position that Christ is one Person in two complete natures (divine and human), the natures preserved without confusion, change, division, or separation. The Chalcedonian Definition was incorporated from Leo's Tome and from the Cappadocian and Cyrilline traditions. Several Eastern Christian communities rejected Chalcedon as crypto-Nestorian and continued to hold one-nature Christological formulations; these are now collectively called the Oriental Orthodox churches (Coptic Orthodox, Ethiopian Orthodox, Syriac Orthodox, Armenian Apostolic, Eritrean Orthodox, Malankara Indian Orthodox). Modern scholarly study has produced substantive ecumenical dialogue between Chalcedonian-affirming and Oriental Orthodox churches; some contemporary scholars argue that the Oriental Orthodox position is properly miaphysite (one-united-nature, drawing on Cyril of Alexandria's formula mia physis tou theou logou sesarkomene, one nature of the divine Word incarnate) rather than strictly Eutychian-Monophysite. The patriarchal-Reformed reader receives the Chalcedonian Definition as orthodox and engages the Oriental Orthodox question with appropriate ecumenical care; the Eutychian-Monophysite position itself is unambiguously heretical.