The Сасаниды, or the Sasanian Empire, was a significant Persian empire that existed from 224 to 651 CE. It was founded by Ardashir I after defeating the Parthian Empire. The Sasanian Empire is known for its achievements in art, architecture, and science, as well as its role in the development of Zoroastrianism, the dominant religion of the time. The empire reached its height under rulers like Khosrow I and Khosrow II, expanding its territory across the Middle East, including parts of modern-day Iran, Iraq, and Armenia. The Sasanian Empire was a major rival to the Byzantine Empire and played a crucial role in the cultural and political landscape of the ancient world.