Pope Leo I (represented at the council by his legate) as well as the Patriarch of Constantinople held a position that in Christ there are two natures – a divine one and a human one at the same time, one beside the other, indivisible, however this was not accepted by the so-called monophysists, convinced of the one, divine nature of Christ. They claimed, led by a Constantinople monk Eutyches, that the human nature of Christ after the Incarnation, was as if absorbed by the divine one “just as a drop of honey melts in the sea…” This, it would seem rater academic quarrel had very important repercussions. The view of Eutyches was condemned at the council and deemed a heresy. The official, meaning orthodox doctrine prevalent until this very day, was not however, accepted by some of the patriarchs and clergy from Syria, Palestine and Egypt, who participated in the council. At this very moment Christianity lost its unity. The consequence of differing opinions on the nature of Christ, was the creation of a group of monophysite Churches, which never again found common ground with the pope in Rome or the patriarch in Constantinople. Out of these Churches arose such Orthodox Churches as the Coptic, Ethiopian, Eritrean, Syrian, Indian, Armenian and others.

Ecumenical dialogue between these Churches and the Eastern Orthodox Church was not undertaken until the XX century and it continues to this very day, as is the case with the Roman Catholic Church as well.