Persian EmpireAchaemenids, the founders of the Persian Empire, are credited with creating the first major multinational empire in the region due to the vast territories they conquered. Cyrus, the first Achaemenid king, ruled Anshan and originally was a vassal of Media. Gradually he attained the support of most Persian and Median tribes, overthrew the Median king, and became the ruler of both the Persians and the Medes in 549 b.c. at Ecbatana (Agbatana), present-day Hamadan.