 Complete the following phrase:  After his defeat, Yazdegerd sought refuge at a miller near Marw, who, however, murdered him in 651. According to Kia, the miller had reportedly killed Yazdegerd in order to obtain his jewelry, whilst the Cambridge History of Iran states that the miller was sent by Mahoe Suri. Regardless, the death of Yazdegerd marked the end of the Sasanian Empire, and made it less difficult for the Arabs to conquer the rest of Iran. All of Khorasan was soon conquered by the Arabs, who would use it as a base to 