
Xerxes, the King of Persia, led a massive invasion of Greece in 480 BC. His army, numbering over a million strong, marched through Thrace and Macedonia and crossed the Hellespont into Asia Minor. The Greeks, under the leadership of Themistocles, were heavily outnumbered, but they were able to defeat the Persian fleet at the Battle of Salamis. Xerxes was forced to retreat, and his invasion of Greece was a failure.