BC. In 510 BC, when Aeschylus was 15 years old, Cleomenes I expelled the sons of Peisistratus from Athens, and Cleisthenes came to power. Cleisthenes' reforms included a system of registration that emphasized the importance of the deme over family tradition. In the last decade of the 6th century, Aeschylus and his family were living in the deme of Eleusis. The Persian Wars played a large role in Aeschylus' life and career. In 490 BC, he and his brother Cynegeirus fought to defend Athens against the invading army of Darius I of Persia at the Battle of Marathon. The Athenians emerged triumphant, and the victory was celebrated across the city-states of Greece. Cynegeirus was killed while trying to prevent a Persian ship retreating from the shore, for which his countrymen extolled him as a hero. In 480 BC, Aeschylus was called into military service again, together with his younger brother Ameinias, against Xerxes I's invading forces at the Battle of Salamis. Aeschylus also fought at the Battle of Plataea in 479 BC. Ion of Chios was a witness for Aeschylus' war record and his contribution in Salamis. Salamis holds a prominent place in The Persians, his oldest surviving play, which was performed in 472 BC and won first prize at the Dionysia. Aeschylus was one of many Greeks who were initiated into the Eleusinian Mysteries, an ancient cult of Demeter based in his home town of Eleusis. According to Aristotle, Aeschylus was accused of asebeia (impiety) for revealing some of the cult's secrets on stage. Other sources claim that an angry mob tried to kill Aeschylus on the spot but he fled the scene. Heracleides of Pontus asserts that the audience tried to stone Aeschylus. Aeschylus took refuge at the altar in the orchestra of the Theater of Dionysus. He pleaded ignorance at his trial. He was acquitted, with the jury sympathetic to the military service of him and his brothers during the Persian Wars. According to the 2nd-century AD author Aelian, Aeschylus' younger brother Ameinias helped to acquit Aeschylus by showing the jury the stump of the hand he had lost at Salamis, where he was voted bravest warrior. The truth is that the award for bravery at Salamis went not to Aeschylus' brother but to Ameinias of Pallene. Aeschylus travelled to Sicily once or twice in the 470s BC, having been invited by Hiero I, tyrant of Syracuse,