History of Iran
The Achaemenid or Achaemenian Empire also called the First Persian Empire, was an ancient Iranian empire that was based in Western Asia and founded by Cyrus the Great in 550 BC. It reached its greatest extent under Xerxes I , who conquered most of northern and central ancient Greece. At its greatest territorial extent, the Achaemenid Empire stretched from the Balkans and Eastern Europe in the west to the Indus Valley in the east. The empire was larger than any previous empire in history, spanning a total of 5.5 million square kilometers (2.1 million square miles).
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