Complete the following paragraph about one of the persian wars

when his father died, (cyrus the great, darius, xerxes i, or cambyses) decided to continue the war with the greeks. he spent 10 years preparing his army and navy to return to greece. the greeks, however, were prepared for the persians to return. they united with the (spartans, babylonians, or athenians) who were known for their military skill. after the battle of (marathon, plataea, or thermopylae), the persians lost and were forced to leave greece.