Regarding Darius I (Darius the Great), he was one of the most prominent kings of the Achaemenid Empire, ruling from 522 BCE to 486 BCE. He is known for his military conquests, administrative reforms, and the construction of the ceremonial capital, Persepolis. His reign marked the peak of the empire, expanding it to its largest territorial extent. Darius also introduced a standardized currency, created efficient road systems, and established a strong bureaucratic government.