Mihrdat succeeded his father, Varaz-Bakur known as Aspacures to the contemporaneous historian Ammianus Marcellinus and installed by Shapur II, the Sassanid king of Iran on the place of his nephew Sauromaces.
Aspacures indicated that he had considered defecting to Rome, but feared for the life of his son Vitra, who was by then a hostage at the Sassanid court.
[1] He was permitted to retain the control of northeastern Iberia, while Sauromaces was established in southwest.
This situation is reflected in Leonti Mroveli’s story of defection of the people of Klarjeti (in Iberia’s southwest) to the Romans.
[2] After the Roman defeat at Adrianople, Sauromaces was probably expelled in 378 and Aspacures presumably regained the whole kingdom.