Ardashir I, an Iranian prince, founded the Sasanian Empire following the decline of Parthia, which was weakened by internal strife and pressures from Rome. After defeating the last Parthian king, Artabanus IV, at the Battle of Hormozdgan in 224, Ardashir set out to restore the glory of the Achaemenid Empire by expanding Iran's territories. Under the Sasanian rule, the empire stretched from the eastern Mediterranean, including Anatolia and Egypt, to parts of modern-day Pakistan. It also extended across southern Arabia, the Caucasus, and Central Asia. According to mythology, the Derafsh Kaviani served as the vexilloid of the Sasanian Empire.
The Sasanian period was marked by significant advancements in culture, architecture, and religion. Zoroastrianism became the state religion, shaping the empire's identity and influencing its governance. The Sasanians promoted a rich cultural life, characterized by advancements in art, science, and philosophy. They established grand cities with impressive architecture, including palaces, fire temples, and public spaces that highlighted their achievements.