The conflict escalated when King Darius I sent heralds to the Greek city-states demanding 'earth and water' as a token of submission. Many submitted, but Athens and Sparta remained defiant; Athens threw the heralds into a pit, and Sparta threw them into a well.
In 490 BC, Darius launched a punitive expedition. At the Battle of Marathon , the Athenian general Miltiades employed a brilliant strategy. He weakened his center and strengthened his flanks, luring the Persian infantry in before enveloping them. The result was a stunning Greek victory that proved the Persian war machine could be beaten.
During the ten-year interlude, Athens struck a rich vein of silver at Laurium. The foresight of Themistocles convinced the Athenians to use this wealth to build a massive fleet of triremes, a decision that would save Greece.
In 480 BC, Darius's son Xerxes I returned with a colossal force. His invasion was a logistical marvel, featuring pontoon bridges across the Hellespont and a canal cut through the Mount Athos peninsula to avoid the storms that had wrecked a previous fleet.
The Greeks attempted to hold the pass at Thermopylae . King Leonidas and 300 Spartans, along with other allies, held off the massive Persian army for days. They were only defeated after a local traitor, Ephialtes, revealed a mountain path to the Persians, allowing them to outflank the Greeks. The Spartans fought to the death to buy time for the rest of Greece.
Following Thermopylae , the road to Athens was open. The Persians sacked the city and burned the Acropolis. However, the Athenians had already evacuated to the island of Salamis , pinning their hopes on their navy.
At Salamis , Themistocles used a ruse, sending a false message to Xerxes claiming the Greeks were in disarray and planning to flee. Xerxes took the bait and sent his fleet into the narrow straits, where their numbers became a hindrance. The Greek triremes rammed and destroyed the Persian fleet in a decisive naval victory.
Xerxes returned to Persia, leaving Mardonius to finish the conquest. In 479 BC, at the Battle of Plataea , the largest Greek army ever assembled, led by the Spartan Pausanias, crushed the Persian forces and killed Mardonius. On the same day, at the Battle of Mycale , the Greek fleet destroyed the remnants of the Persian navy in Ionia, effectively ending the Persian threat.
