The Sasanian Empire, founded by Ardashir I, was a prominent power for over 400 years, rivaling the Roman and later Byzantine Empires. At its peak, it covered modern Iran, Iraq, Azerbaijan, Armenia, Georgia, parts of Russia, Lebanon, Jordan, Palestine, Israel, parts of Afghanistan, Turkey, Syria, Pakistan, Central Asia, Eastern Arabia, and parts of Egypt.^[27]

The empire's history was marked by frequent wars with the Byzantine Empire, a continuation of the Roman-Parthian Wars. These wars, starting in the 1st century BCE and lasting until the 7th century CE, are considered the longest-lasting conflicts in human history. A notable victory for the Persians was at the Battle of Edessa in 260, where Emperor Valerian was captured.

Under Khosrow II (590–628), the empire expanded, annexing Egypt, Jordan, Palestine, and Lebanon, and was known as Erânshahr ("Dominion of the Aryans").^[28] The Sasanians clashed with the Romano-Byzantine armies over Anatolia, the Caucasus, Mesopotamia, Armenia, and the Levant. An uneasy peace was established under Justinian I through tribute payment.

However, conflicts resumed following the deposition of Byzantine Emperor Maurice, leading to several battles and eventually a peace settlement. The Roman-Persian Wars concluded with the Byzantine–Sasanian War of 602–628, culminating in the siege of Constantinople. The Sasanian Empire fell to the Arab Conquest at the Battle of al-Qādisiyyah in 632, marking the empire's end.

The Sasanian period, considered highly influential in Iranian history, greatly impacted world civilization. This era saw the peak of Persian culture and influenced Roman civilization, with its cultural reach extending to Western Europe, Africa, China, and India. It played a significant role in shaping medieval European and Asiatic art.

The Sasanian dynasty's culture profoundly influenced the Islamic world, transforming the Islamic conquest of Iran into a Persian Renaissance. Many aspects of what later became Islamic culture, including architecture, writing, and other contributions, were derived from the Sasanians.