Cyrus the Great founded the Persian Empire by conquering the Median kingdom in the 6th century BC. The Persian Empire went on to dominate Mesopotamia for over 800 years and conquered several other empires including Egypt, Syria, parts of Asia Minor, and India. The Persian government, called a Satrapy, was similar to the Roman republic and divided the empire into provinces ruled by governors. Darius I helped expand the empire further and established a new type of centralized government during his rule in the 5th century BC.