Darius was an ancient Persian king who ruled from 522 to 486 BC. He was the son of Hystaspes and succeeded Cyrus the Great as ruler of the Achaemenid Empire. His reign is remembered for his military campaigns, which included a successful invasion of Greece and the conquest of Thrace and Macedonia. He is also known for his construction of the Royal Road, which connected Susa to Sardis. Xerxes was Darius' son and successor, who reigned from 486 to 465 BC. PERSIA was the ancient kingdom that Darius ruled over, and it was located in what is now modern-day Iran. Darius' main FOE during his reign was the Greek city-states, which he attempted to conquer. Milhaud was a French composer and teacher who wrote music inspired by Darius' reign, including the opera 'Darius Milhaud'.