Hippias (hĬp´ēəs), tyrant (527 BC–510 BC) of Athens, eldest son of Pisistratus. Hippias governed Athens after the death of his father. His younger brother Hipparchus was closely associated in office with him until Hipparchus was assassinated in 514 BC At first Hippias attempted to work with his opponents, the Alcmaeonidae, but his rule became harsher as the Persians advanced. In 510 BC he was overthrown by the Alcmaeonidae and the Spartans and went into exile. He lived at the court of Darius and was with the Persian forces at Marathon.