Yazdegerd III (also spelled Yazdgerd III and Yazdgird III; 𐭩𐭦𐭣𐭪𐭥𐭲𐭩) was the last Sasanian King of Kings of Iran from 632 to 651. His father was Shahriyar and his grandfather was Khosrow II.
Ascending the throne at the age of eight, the young shah lacked authority and reigned as figurehead, whilst real power was in the hands of the army commanders, courtiers, and powerful members of the aristocracy, who engaged in internecine warfare. The Sasanian Empire was weakened severely by these internal conflicts, resulting in invasions by the Göktürks from the east, and Khazars from the west. It was, however, the Arabs, united under the banner of Islam, who dealt the decisive blow. Yazdegerd was unable to contain the Arab invasion of Iran, and spent most of his reign fleeing from one province to another in the vain hope of raising an army. Yazdegerd met his end at the hands of a miller near Marw in 651, bringing an end to the last pre-Islamic Iranian empire after more than 400 years of rule.