When news of Shiruy's death reached General Guraz in the realm of Rome, he learned that the Sasanian crown had fallen to the young child-king Ardashir. Concealing his insatiable ambition beneath feigned laments for Khosrow Parviz, Guraz dispatched a swift courier to Piroz Khosrow, the chief minister and treasurer of the Iranian court. In his letter, Guraz incited Piroz Khosrow to do away with the boy-king, promising ultimate favors while threatening to sweep down with an overwhelming Byzantine host should the conspiracy be betrayed.
Swayed by treachery and fear, Piroz Khosrow embraced the foul plot. One dark night, inside the royal halls of Ctesiphon, young Ardashir hosted a magnificent banquet where wine flowed without measure. As midnight arrived, the court companions and minstrels succumbed to heavy drunken sleep. The wicked Piroz Khosrow dismissed the remaining attendants until he alone remained with the vulnerable king. Seizing his moment, the villain sprang forward and clamped his hands over the child-king's mouth, suffocating Ardashir until life left his body. The palace was at once seized by Piroz Khosrow's armed conspirators, and a camel-rider was sent racing toward Guraz. Overjoyed by the success of his scheme, Guraz assembled a colossal host that darkened the lands, marching like a hurricane toward defenseless Ctesiphon to seize the throne.