Emperor Darius wanted the Greeks merely to confirm that they were his subjects by sending him a jar of water and a box of soil in symbolic tribute. The Greeks refused. Darius collected an army to go teach the Greeks a lesson they would never forget, but the very size of his army was as much a liability as an asset: How do you direct so many men at such a distance? How do you keep them supplied? Darius had ignored the first principle of military strategy: never fight a land war in Europe. In the end, it was the Greeks who taught the Persians an unforgettable lesson—a lesson that they quickly
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