PATRIARCH (M.E. and O. Fr. patriarche, Lat. patriarcha, Gr. πατριάρχης, from πατριά, clan, and ἀρχή, rule), originally the father or chief of a tribe, in this sense now used more especially of the “patriarchs” of the Old Testament, i.e. Abraham, Isaac and Jacob, with their forefathers, and the twelve sons of Jacob. In late Jewish history the title “patriarch” (Heb. nāsī, prince, chief) was given to the head of the sanhedrim in Palestine, and is sometimes, though wrongly, applied to the “exilarch,” a head of the Jewish college at Babylon.

In the early centuries of the Christian Church the designation “patriarch” was applied, like “archbishop,” to bishops of the more important sees as a merely honorary style. It developed into a title implying jurisdiction over metropolitans, partly as a result of the organization of the empire into “dioceses,” partly owing to the ambition of the greater metropolitan bishops, which had early led them to claim and exercise authority in neighbouring metropolitanates. At the Council of Chalcedon (451) the patriarchs still bore the title of “exarch”; it was not till the 7th century that that of “patriarch” was fixed as proper to the bishops of Constantinople, Alexandria, Antioch and Jerusalem, “exarch” being reserved for those of Ephesus and Caesarea, who had fallen to a lower rank. In the West the only patriarch in the fully developed sense of the Eastern Church has been the bishop of Rome, who is patriarch as well as pope.