The Sasanian Dynasty was a Persian empire that ruled from 224 to 651 CE. It was founded by Ardashir I after defeating the last ruler of the Parthian Empire. The dynasty is known for its achievements in art, architecture, and culture, as well as for its conflicts with the Roman Empire and later the Byzantine Empire. The Sasanian period saw the establishment of Zoroastrianism as the state religion, influencing the region's culture and society. The dynasty reached its peak under Khosrow I, known for his administrative reforms and military successes. The Sasanian Empire ultimately fell to the Arab conquests, leading to significant changes in the region.