Early in Peroz's reign, tensions began to rise between Iran and Byzantium. In the mid-460s, the Byzantines discovered that their general Ardaburius had been secretly corresponding with the Iranian court, urging Peroz to attack the Byzantines, with the promise of military support and presumably also intelligence. Ardaburius's letters were intercepted and given to Byzantine emperor Leo I (), who had him removed from office and summoned to the capital, Constantinople. Ardaburius's fate is not known. Leo responded to the Iranian activity by reinforcing his borders with them, which included the fortification of Callinicum in Syria.
