Дарий I, also known as Дарий Великий, was the third king of the Ахаеменидская империя, ruling from 522 to 486 до н.э. He is best known for his administrative reforms, which helped to unify and strengthen the vast empire. Under his leadership, the empire expanded significantly, reaching its greatest territorial extent. Дарий I is also famous for his construction projects, including the impressive Персеполь, which served as a ceremonial capital. He introduced a standardized system of weights and measures, as well as a postal system, which improved communication across the empire. His reign marked a significant period in ancient Persian history.