Abgar V
Abgar V the Black or Abgarus V of Edessa (Syriac: ܐܒܓܪ ܚܡܝܫܝܐ ܐܘܟܡܐ; ʾAḇgar Ḥəmīšāyā ʾUkkāmā, Armenian: Աբգար Ե Եդեսացի; Abgar Ye Yedesatsi, Ancient Greek: Ἄβγαρος Abgaros) BC 4 – AD 7 and AD 13–50) was an historical Armenian ruler of the kingdom of Osroene, holding his capital at Edessa. (Compare to the region that was referred to as Armenian Mesopotamia by the Greeks and Aram in the Old Testament).
According to an ancient Christian legend, first documented by Eusebius, he was converted to Christianity by Addai, one of the Seventy-two Disciples. According to Armenian historian Moses of Khorene, writing 400 years after his death, he was Sanatruk's relative.
The legend of King Abgar
Abgar V was, according to Syriac tradition, one of the first Christian kings in history, having been converted to the faith by the Apostle Thaddeus of Edessa. Other accounts regard this as mere legend, equating the Abgar in the story with the Syrian Abgar IX, a late 2nd-century convert to Christianity. Moses of Khoren suggests that the name of the legendary figure is a corruption of an individual's title: "…Because of his uncommon modesty and wisdom, and his old age, this Abgaros was given the title of "Avag Hair" (Senior Father in Armenian). The Greeks and Syrians, unable to articulate his name correctly, called him Abgar."