One of the Oriental Orthodox Churches. It emerged as a separate body in the aftermath of the Council of Chalcedon (451), whose Christology it refused to accept. An independent hierarchy under the Patr. of Antioch was built up in the 6th cent. Numbers were reduced in the 14th cent. by Mongol invasions, in the 18th cent. by the establishment of a separate Uniat patriarchate (see Syrian Catholics), and at the turn of the 20th cent. by massacres at the hands of the Turks. They may now number c.200,000 in the Middle East, 100,000 in Europe and N. and S. America, and perhaps a million in South India (Malabar Christians). Since the 1960s large numbers have emigrated to W. Europe. Their liturgical language is Syriac. They are also known as Jacobites or Monophysites (qq.v).