An Arsacid prince named Sanatruk (whom Faustus of Byzantium calls Sanesan, king of Maskut, and identifies as Khosrov's brother) raised a rebellion to take the throne.
[3] In the southwest, the bdeashkh of Arzanene Bakur revolted against the Arsacid monarchy with the support of the Sasanian king Shapur II.
[3] Forces loyal to Khosrov rallied under Sparapet Vache Mamikonian and destroyed Sanatruk's army in a surprise attack, killing the pretender in a battle near Oshakan.
[3] Khosrov rewarded his top generals Vache Mamikonian and Vahan Amatuni and the other nakharars that had remained loyal to him with land and other lavish gifts.
[3] Vache Mamikonian and Vahan Amatuni led the Armenian army to victory against the Persian invaders in a battle near the southeastern coast of Lake Van.
[3] After this, Khosrov decreed that all nakharars with a force larger than 1,000 soldiers were obligated to live at the royal court, where the king could exercise control over them.