558-486 BC. King of Persia 521-48 BC. A 
member of a younger branch of the Achaemenid 
dynasty, he won the throne from the usurper 
Gaumata (died 522 BC) and reorganized the 
government. In 512 BC he marched against the 
Scythians, a people north of the Black Sea, 
and subjugated Thrace and Macedonia. An 
expedition in 492 BC to crush a rebellion in 
Greece failed, and the army sent into Attica 
490 BC was defeated at the battle of 
Marathon. Darius had an account of his reign 
inscribed on the mountain at Behistun, 
Persia.