The Muslim armies managed to defeat the Sasanian troops in several decisive battles in the middle of the seventh century AD and establish the rule of the young Islamic Empire in the former Sasanian territories, and large parts of the Byzantine Empire, by the beginning of the eighth century. The Battle of Qadissiya in November of 636 saw the defea= t of the Sasanian troops under the command of Rustamson of Farrokhzad, while by 638 the Muslims had raided Ctesiphon, the capital of the Sasanians in Mesopotamia (Sasanian Asorestan). The Battle of Nahavand in 641 saw the destruction of a Sasanian alliance, and in 651, the last Sasanian Emperor,Yazdgerd III, was killed while fleeing to China (Source: Iranologie.com).
Shia Islam in Iran: Legacy of Muslim Conquest of Persia
