 Prior to being elected as Catholicos-Patriarch, Mar Addai II served as Bishop of Baghdad.He was later elevated to the rank of Metropolitan of Iraq in September 1968, after the schism separating the Ancient Church of the East from the Assyrian Church of the East.Together with Mar Aprem Mooken and Mar Poulose Poulose, Mar Addai consecrated Mar Thoma Darmo as the Patriarch of the Ancient Church of the East in October 1968.