Matters were still more complicated when the Western Christians of Edessa found themselves unable to accept the ruling of Chalcedon against Monophysitism in 451 (see Monophysites), and there came to be three parties: Nestorians (q.v.), Jacobites (see Jacobite Church) and Melchites.
There is no doubt that the disintegration caused by monophysitism largely facilitated the rapid and easy victory of Islam in Syria and Egypt.
A few years later Jacob Baradaeus, with Edessa as centre of his bishopric, was carrying on the propaganda of Monophysitism which won for the adherents of that creed the name of Jacobites.
The decree for the Armenians was published on the 2 2nd of November 1 439; they accepted the filioque and the Athanasian creed, rejected Monophysitism and Monothelitism, agreed to the developed scholastic doctrine concerning the seven sacraments, and conformed their calendar to the Western in certain points.
Of course this does not mean that Harnack considers monophysitism nearer the historic truth, or nearer the normal type of Christian thought.
In Egypt, however, monophysitism was as strong as ever, and soon at Constantinople the arrogance of Rome caused a reaction, led by Theodora, the wife of the new emperor Justinian (527565).
Among the Western bishops, who were less disposed both to Monophysitism and to subservience, and especially by those of Africa, the edict was earnestly resisted.
Meanwhile monophysitism had split into several factions.
He entered a monastery, but under the influence of Western missionaries he became possessed with the idea of propagating Western ideas and culture in Armenia, and of converting the Armenian Church from its monophysitism and uniting it to the Latin Church.