Eastern Orthodoxy

The Oriental Orthodox and Eastern Orthodox churches are two distinct bodies of local churches. The churches within each body share full communion, although there is not official communion between the two bodies. Both consider themselves to be the original church, from which the West was divided in the 5th and 11th centuries, respectively (after the 3rd and 7th Ecumenical councils).
Many theologians of the Eastern and Oriental Orthodoxies engage in theological dialogue with each other and with some of the Western churches, though short of full communion. The Eastern Orthodox have participated in the interfaith movement, with students active in the World Student Christian Federation since the late 19th century and some Orthodox patriarchs enlisting their communions as charter members of the World Council of Churches. (wiki)