This heresy was the subject of the Second Council of (*) Constantinople, and was originally formulated by Eutyches.
Peter the Fuller supported this belief by adding a clause to the Trisagion, and Jacob Baradaeus was another noted proponent of this belief. The Theopaschite formula was one attempt to reconcile this belief, supporters of which opposed certain writings of Theodoret, Ibas of Edessa, and Theodore of Mopseustia; those works condemned by this belief were known as the "Three Chapters." Followers of this belief also rejected the Tome of Leo I, and Felix III excommunicated Acacius for promulgating an edict attempting a restitution with this belief, the Henotikon. This heresy was the subject of the Second Council of (*) Constantinople, and was originally formulated by Eutyches. Conceived as a response to Nestorianism, this heresy rejected the central teachings of the Council of Chalcedon. FTP, name this heresy still held by the Armenian and Coptic churches, whose Greek name reflects its belief that Christ had just a single, unitary nature.
Peter the Fuller supported this belief by adding a clause to the Trisagion, and Jacob Baradaeus was another noted proponent of this belief.
{monophysit}ism [accept {miaphysit}ism, I guess]