Historically, the title originated as ecclesiastical designation for primates of the Church of the East.
This title is held by the Melkite, Greek Orthodox, Syriac Orthodox and the Syriac Catholic patriarchs of Antioch, and also by primates of some other sees, belonging to several Eastern Christian denominations.
The patriarchs of the Church of the East traditionally also carry the title of catholicos.
The patriarchs of the East of the Oriental Orthodox churches sometimes also carry the title of catholicos or pope.
Each patriarch of the east has authority over all bishops of a particular eastern rite church.