St. Addai is purported by Eusebius to have visited King Abgar of Edessa, healing him and preaching to him. The Syriac account of this story is titled the Teaching of Addai, and there are questions about its historicity. The story possibly dates instead from the third century and may have been used in polemics against the Manichaean "apostle" also named Addai.The Syriac liturgy referred to as the Liturgy of Addai and Mari, which originated around the...