The Achaemenid Empire or Achaemenian Empire (/əˈkiːmənɪd/; Old Persian: 𐎧𐏁𐏂, Xšāça, lit. 'The Empire' or 'The Kingdom'), also called the First Persian Empire, was an ancient Iranian empire founded by Cyrus the Great in 550 BC. Based in Western Asia, it was contemporarily the largest empire in history, spanning a total of 5.5 million square kilometres (2.1 million square miles) from the Balkans and Egypt in the west to Central Asia and the Indus Valley in the east.