1909 Catholic Dictionary
(Addeus, or Thaddeus) Mentioned in the Syriac document, "Doctrine of Addai," as one of the 72 disciples of Christ, who preached at Edessa, converting King Abgar V and a great number of his people. The "Doctrine" is only a legend. No doubt there were Christians in Edessa before the end of the 2nd century but its first Christian king as Abgar IX (179-214). Feast, various dates.