Home - Greek Orthodox Archdiocese of America Orthodox Christianity is a communion of self governing Churches, united by a common faith and spirituality. The Greek Orthodox Archdiocese of America, headquartered in New York City, is an Eparchy of the Ecumenical Patriarchate. The mission of the Archdiocese is to proclaim the Gospel of Christ, to teach and spread the Orthodox Christian Faith, to energize, cultivate, and guide the life of the Church in the United States of America according to the Orthodox Christian Faith and Tradition.