Khosrow II, also known as Khosrow Parviz, is considered to be the last great Sasanian king of Iran, ruling from 590 to 628, with an interruption of one year.
Khosrow II was the son of Hormizd IV, and the grandson of Khosrow I. He was the last king of Iran to have a lengthy reign before the Muslim conquest of Iran, which began five years after his execution. He lost his throne, then recovered it with the help of the Byzantine emperor Maurice, and, a decade later, went on to emulate the feats of the Achaemenids, conquering the rich Roman provinces of the Middle East; much of his reign was spent in wars with the Byzantine Empire and struggling against usurpers such as Bahram Chobin and Vistahm.
After the Byzantines killed Maurice, Khosrow II began a war in 602 against the Byzantines. Khosrow II's forces captured much of the Byzantine Empire's territories, earning the king the epithet "the Victorious". A siege of the Byzantine capital of Constantinople in 626 was unsuccessful, and Heraclius, now allied with Turks, started a successful risky counterattack deep into Persia's heartland.