Original: In 490 BC, Aeschylus and his brother Cynegeirus fought to defend Athens against Darius' invading Persian army at the Battle of Marathon.
Simplified: In 490 BC the Persian army, led by Darius, landed in Greece and tried to take it over. Aeschylus, and his brother Cynegeirus, joined the army from Athens and fought against the Persians at the Battle of Marathon.