Armenian Church, autonomous Christian church, sometimes also called the Gregorian Church. Its head, a primate of honor only, is the catholicos of Yejmiadzin, Armenia; Karekin II became catholicos in 1999. His rule is shared by the patriarchs of Jerusalem and Constantinople and by the catholicos of Sis (Cilicia). In general, Armenian practices resemble those of other Eastern churches; the priests may marry and communion is distributed in both bread and wine, although the use of unleavened bread is a Western practice. The liturgical language is classical Armenian. Armenia became Christian at the end of the 3d cent. through the missionary work of St. Gregory the Illuminator. In the next century the young church made itself autonomous, apparently because of the efforts of the metropolitan bishop of Caesarea, St. Basil the Great, to impose certain reforms. After the Council of Chalcedon the Armenians rejected the orthodox position; this adoption, at least tacit, of Monophysitism completed the isolation of the Armenian Church from the rest of Christendom. Part of the Armenian Church reunited with Rome temporarily in the 13th and 14th cent., and missionary work by the Roman Church in the 14th cent. resulted in many converts. In 1740 the Catholic Armenian rite was officially organized, in communion with the pope but under its own patriarch. Today there are Armenian churches in every continent.
See P. C. Gulesserian, The Armenian Church (tr. 1939, repr. 1970); D. Attwater, The Christian Churches of the East (2 vol., rev. ed. 1961).