MOTHER CHURCH. This appellation is used today to denote the local and established Orthodox Church, which is the source of another community and often the latter’s jurisdictional authority. It is in common use in Orthodox groups in “diaspora,” i.e., regions such as the Americas, Western Europe, Australia, or Oceania, or in missionary territories such as Africa or the Far East. Believers in these areas look to a “mother church” in the home countries that are traditionally Orthodox for direction and hierarchical supervision. The ancient title belonged preeminently to Jerusalem: “Zion, the mother of churches.” Later in the West and East, respectively, Rome (q.v.) acquired the title of “mother” for its successful conversion of northern Europe, and Constantinople (q.v.) for its having brought Christianity to the southern and eastern Slavs.