1) The Persians, led by Cyrus and Cambysus, conquered Babylon and freed the Jews, and attempted to conquer Egypt. 2) In 490 BC, the Persians under Darius launched a second invasion of Greece after their first attempt failed. They were defeated by the Athenians at the Battle of Marathon. 3) In 480 BC, Xerxes led a massive Persian army in a second invasion of Greece. They were defeated by the Greeks at the naval Battle of Salamis, ending Persian efforts to conquer Greece.