Among the
Eastern Orthodox faithful, Addai was a disciple of Christ sent by
St. Thomas the Apostle to
Edessa in order to heal
King Abgar V of
Osroene, who had fallen ill. He stayed to evangelize, and so converted Abgar—or Agbar, or in one Latin version "Acbar" — and his people including
Saint Aggai and
Saint Mari. The story of how King Abgarus V and
Jesus had corresponded was first recounted in the 4th century by the church historian
Eusebius of Caesarea. In the origin of the legend, Eusebius had been shown documents purporting to contain the official correspondence that passed between Abgar and Jesus, and he was well enough convinced by their authenticity to quote them extensively in his
Ecclesiastical History. According to Eusebius: The story of the healing and Addai's evangelizing efforts resulted in the growing of Christian communities in southern Armenia, northern Mesopotamia and in Syria east of Antioch. Thaddeus' story is embodied in the Syriac document,
Doctrine of Addai, which recounts the role of Addai and makes him one of the
72 Apostles sent out to spread the
Christian faith. By the time the
legend had returned to
Syria, the purported site of the miraculous
image, it had been embroidered into a tissue of miraculous happenings. ==Various traditions==