The Sasanian Empire, named after the ancestor Sasan, was founded in 224 CE when Ardashir I overthrew the last Parthian king Artabanus IV. The Sasanians saw themselves as the successors to the Achaemenid Empire of Cyrus and Darius, seeking to restore Persian glory and Zoroastrian orthodoxy.
At its height, the empire stretched from the Euphrates to the Indus, from the Caucasus to the Persian Gulf. The Sasanians developed a highly centralized bureaucratic state, a sophisticated legal system, and made lasting contributions to art, architecture, music, and philosophy that would influence the Islamic civilization that followed.
The empire was known for its constant rivalry with Rome and later Byzantium, fighting numerous wars over control of Mesopotamia, Armenia, and the trade routes of the ancient world. This rivalry only ended with the Arab conquests of the 7th century, which brought both empires to their knees.