 Complete the following phrase:  On 25 February, Sheroe, along with his commander Aspad Gushnasp, captured Ctesiphon and imprisoned Khosrow II. He then proclaimed himself as shah of the Sasanian Empire and assumed the dynastic name of Kavad II. He proceeded to have all his brothers and half-brothers executed, including the heir Mardanshah, who was Khosrows favourite son. The murder of all his brothers, all well-educated, valiant, and chivalrous men, strapped the Sasanian dynasty of a future competent ruler, and has been described as a mad rampage and reckless. Three days later he ordered Mihr Hormozd to execute his father. However, after the regicide of his father, Kavad also proceeded to have Mihr Hormozd killed. With the agreement of the Iranian nobles, he then made peace with the victorious emperor Heraclius, which allowed the Byzantines to regain all their lost territories, their captured soldiers, a war indemnity, along with the True Cross and other relics that were 