Persians

Persian Army and Mercenary Forces - East of India

Following the failure of the Ionian Revolt (499 BC - 494 BC), Darius I , King of Persia was intent on subjugating the Greeks and punishing them for their part in the revolt.
In 492 BC Darius dispatched an army under his son-in-law, Mardonius. In September 490 BC the heavily armored Greek army with it's long spears met the lightly armored army of Persia with its archers and short swords. The Greeks won a great victory.
It was the first time the Greeks had bested the Persians on land, and "their victory endowed the Greeks with a faith in their destiny which was to endure for three centuries."