Darius I, known as Darius the Great, was the third King of Kings of the Achaemenid Empire. He ruled the empire at its peak, controlling a vast territory from the Balkans to the Indus Valley.
He was a brilliant administrator who divided the empire into provinces (satrapies), built the Royal Road, and established a uniform monetary system. His rule brought stability and prosperity to the Persian world.
However, he is also remembered for his failed attempt to punish Athens for supporting the Ionian Revolt. His forces were unexpectedly defeated at the Battle of Marathon in 490 BC, a loss he swore to avenge but died before he could.