Pentarchy

   Greek term for "the rule of five," referring to the Byzantine theory, which evolved in the fifth and sixth centuries (formally sanctioned by Justinian I [q.v.]), that church authority is collective, residing in the five patriarchates (q.v.) of Rome, Constantinople, Alexandria, Antioch, and Jerusalem (qq.v.). It followed that no church council could be called unless all five were present. This theory was contested by the papacy (q.v.), which subsequently claimed exclusive papal primacy (q.v.) over the church, not just honorary primacy among equal partners. The theory was also weakened by the conquest of the Near East by the Arabs (q.v.), since the sees (q.v.) of Alexandria, Antioch, and Jerusalem were no longer a part of Byzantium (q.v.).