Between the Third Ecumenical Council of Ephesus (431 AD) and the Fourth Ecumenical Council of Chalcedon (451 AD), the archbishops of the Eastern and Western Roman Empires (i.e. the archbishops of Alexandria, Antioch, Rome, Constantinople, and Jerusalem, also known as the Archbishops of the Ancient Apostolic Thrones), were given the title of "patriarch". These titles were ratified at the Fourth Ecumenical Council of Chalcedon (451 AD), and henceforth were known historically as the Ancient Patriarchates of the Holy Catholic and Apostolic Orthodox Church or otherwise as the Pentarchy.