Darius I (558-486 BC), called "the Great," was a Persian king. A great conqueror and the chief organizer of the Persian Empire, he is best known for the unsuccessful attack on Greece which ended at Marathon.

A member of a collateral branch of the Achaemenidian royal family, Darius apparently was not close to the throne when Cambyses died in 522 B.C. The story of Darius's accession is told most fully by the Greek Herodotus, whose version clearly reflects the official account set up by Darius's own order in the famous rock inscription at Behistun.

According to Herodotus, Cambyses had had his brother Smerdis (Bardiya) executed, but while Cambyses was absent in Egypt, a Magian priest named Gaumata, trusting in a chance resemblance, put himself forward as Smerdis and seized the throne. Cambyses started back but died en route, and the false Smerdis was generally accepted. Darius, with the...