Eutyches, a heresiarch of the 5th century, born about 380, died about 454. For many years he lived as a priest and archimandrite in the cloisters of Constantinople, where he had more than 300 monks under his direction. He was the head of the party opposed to Nestorius, who, in order not to confound the divine and human natures in Christ, had affirmed that there were in him two distinct persons. Euty-ches, in his zeal for singleness of person in Christ, was led to maintain also that he possessed but one nature; whence his followers were called Monophysites. This opinion became popular in the Alexandrian church, where the doctrines of Nestorius had been most loudly condemned. The rising heresy was examined and condemned by a synod at Constantinople in 448. The influence of Eutyches and his friends obtained from Theodosius II. the reference of the matter to a general council to meet at Ephesus in 449 under the presidency of Dios-corus, a violent Eutychian. Here the triumph of Eutyches was secured by the outcries of monks, the threats of soldiers, and the overbearing violence of the president; and the most prominent hostile bishops were deposed.

Pope Leo refused to recognize the acts of this council, which was known as the Latrocinium, or robber synod, and excommunicated Dios-corus; and at the general council of Chalce-don, in 451, both the doctrines of Nestorius and of Eutyches were condemned. In the 6th century a great revival of the doctrine took place under the auspices of the monk Jacob Baradaeus, who died bishop of Edessa. From him the sect took the name of Jacobites, who still constitute a numerous church in Egypt, Syria, and Abyssinia. The emperor Heraclius sought to mediate between the Monophysites and Catholics, and promulgated a decree in 630, requiring the doctrine to be taught that there were two natures in Christ, but only a single will. Hence the name of Monothelites, the last offshoot of the heresy of Eutyches.