Khusru II, AD 591-628- AR Drachm

The Sasanian Empire, officially Ērānšahr (lit. 'Empire of the Iranians'), was the last pre-Islamic Iranian empire. Named after the House of Sasan, it endured for over four centuries, from 224 to 651, making it the second longest-lived Persian imperial dynasty after the directly preceding Arsacid dynasty of Parthia. It fell to the Rashidun Caliphate during the early Muslim conquests, which marked the beginning of a monumental societal shift by initiating the Islamization of Iran. Upon succeeding the Parthians, the Sasanian dynasty re-established the Iranian nation as a major power in late antiquity, and also continued to compete extensively with the neighbouring Roman Empire. It was founded by Ardashir I, a ruler who rose to power as Parthia weakened amidst internal strife and the Roman–Persian Wars. After defeating Artabanus IV of Parthia during the Battle of Hormozdgan in 224, Ardashir's dynasty replaced that of the Arsacids and promptly set out to restore the legacy of the Achaemenid