The Sasanian dynasty (also known as the Sassanids or the House of Sasan), the last Persian lineage of rulers to achieve hegemony over much of Western Asia before Islam, ruled 224 CE–650 CE. the house of Sasan founded the Sasanian Empire of Iran, It began with Ardashir I, who named the dynasty in honour of his predecessor, Sasan.
The Shahanshah was the sole regent, head of state and head of government of the empire. At times, power shifted de facto to other officials, namely the spahbed. Upon the empire's conquest by the Islamic caliphate in 651, members of the imperial family fled in exile to China following the death of Yazdegerd III, where they would become accepted as members of the imperial court by Emperor Gaozong of Tang. Although there would be numerous attempts to invade Islamic Persia with Chinese support, this branch of Sasanids would remain in China indefinitely. Narsieh, grandson of Yazdegerd and last recorded Sasanid in China, would adopt the surname Li (李) in honor of the Chinese imperial family.
