Saint Mari was converted by Saint Addai. He is said to have had Mar Aggai as his spiritual director. He is also believed to have done missionary work around Nineveh, Nisibis, and along the Euphrates, and is said to have been one of the great apostles to Syria and Persia. He and Addai are credited with the Divine Liturgy of Addai and Mari. Despite the fact that there is little if any concrete information on Mari, he is still venerated as a saint by the Assyrian Church of the East,Chaldean Catholic Church and the Syro Malabar Catholic Church.