Osroene, a kingdom established in 132 BCE by the Nabataeans or Arab tribes from North Arabia, is arguably the first state to have a Christian king when Abgar IX is thought to have accepted Christianity under the guidance of Bardaisan.
Bardaisan had been born in Edessa, a metropolis of Osroene in Assuristan (Assyria).
To indicate the city of his birth his parents called him "Son of the Daisan", the river on which Edessa is situated.
On account of his foreign extraction he is sometimes referred to as "the Parthian" (by Sextus Julius Africanus), or "the Babylonian" (by Porphyrius); and, on account of his later important activity in Armenia, "the Armenian", (by Hippolytus of Rome), while Ephrem the Syrian calls him "philosopher of the Arameans".
His parents, Nuhama and Nah 'siram, must have been people of rank, for their son had been educated with the crown-prince of the Osrhoenic kingdom, at the court of Abgar VIII bar Manu.
Sextus Julius Africanus says that he saw Bardaisan, with bow and arrow, mark the outline of a boy's face with his arrows on a shield which the boy held.
Owing to political disturbances in Edessa, Bardaisan and his parents had moved for a while to Hierapolis (Mabug), a strong center of Babylonianism.
Here the boy had been brought up in the house of a priest, Anuduzbar, learning in this school all the intricacies of Babylonian astrology, a training that will permanently influence his mind and prove the bane of his later life.
At the age of twenty-five, he had happened to hear the homilies of Hystaspes, the Bishop of Edessa, received instruction, was baptized, and even admitted to the dioconate or the priesthood.
"Priesthood", however, may merely imply that he ranked as one of the college of presbyters, for he had remained in the world, had a son called Harmonius, and when Abgar IX, the friend of his youth, ascended the throne in 179, he took his place at court.
He was clearly no ascetic, but dressed in finery "with berylls and caftan", according to Ephrem the Syrian.
According to Michael the Syrian, Bardaisan had besides Harmonius two other sons, called Abgarun and Hasdu.
According to tradition, during his youth he shared the education of a royal prince who afterwards became King of Edessa, perhaps Abgar X bar Manu (reigned Osroene 202-217).
He is said to have converted the prince to Christianity, and may have had an important share in Christianizing the city.
Epiphanius of Salamis and Barhebraeus assert that he was first an orthodox Christian and afterwards an adherent of Valentinus.
His acceptance of Christianity was perfectly sincere; and later stories, that he left the Catholic Church and joined the Valentinian Gnostics out of disappointed ambition, do not deserve much credit.
His royal friend becomes (probably after 202, i.e.
after his visit and honorable reception at Rome) the first Christian king; and both king and philosopher labor to create the first Christian State.
