Answer: Around the 5th century bc, the Persians under Cyrus the Great had rapidly expanded their domain. By the time of Darius I, the Persian empire covered most of southwest Asia and Asia Minor, reaching as far as the easternmost boundaries of Europe. The Persians demanded tribute and respect from all they dominated. The Greek cities in Asia Minor eventually decided to throw off the Persian yoke. Through those revolts, the assistance of the Athenians and the ensuing Battle of Marathon, the wheels had been set in motion to end Persian domination.
