He is known as Pharnabazus in Classical sources, and is commonly identified with the Bartom or Bratman of the medieval Georgian chronicles.
He succeeded upon the death of his father Artag who had been defeated by the Roman general Pompey in 65 BC.
Mirvan returned to Kartli at the head of an Iranian army, killed Bartom and became a king.
Bartom is said to have adopted Kartam, the descendant of Kuji (the alleged ruler of Egrisi in the time of the first Iberian king Parnavaz).
Nevertheless, Kartam's pregnant wife – the daughter of Bartom – fled to Armenia where she gave birth to a son named Aderki.