Cyrus the Great
In 550 BC Cyrus II lead a Persian revolt against Medes, a that they lost to about fifty years ago. His revolt was a success and he won independence for Persia and conquered the Medes. This victory marked the beginning of the Persian Empire. In his rule Cyrus conquered a lot of Southwest Asia, including much of Asia Minor, took over many Geek cities, and then marched south to conquer Mesopotamia. Out of all the people he conquered he let them all keep their customs because he thought this would make them less likely to rebel against him.