According to Eastern Christian tradition, Addai of Edessa or Thaddeus of Edessa was one of the seventy disciples of Jesus.
August 21 (Eastern Orthodox liturgics)
…Holy Forefathers Abraham, Isaac, and Jacob (ca. 2000 BC) Apostle Thaddeus of Edessa, one of the Seventy Apostles (44) Martyr Bassa of Edessa and her sons Theognius, Agapius, and Pistus (305-311…
Abgar receiving the Mandylion from Addai (encaustic icon, Saint Catherine's Monastery, Mount Sinai).
Christ Pantocrator mosaic from Hagia Sophia 2744 x 2900 pixels 3.1 MB