How did Greek city-states defeat the Achaemenian Persian Empire in the Greco-Persian Wars?

The Greek city-states successfully defended their independence against the Achaemenian Persian Empire through a combination of strategic military innovation, tactical maneuvering, and the formation of a collective defense league.12

Key factors in the Greek victory included:

• Strategic Unity: In 481 BCE, a general Greek league was formed to coordinate defense, setting aside internal rivalries to face the existential threat of Persian subjugation.2
• Naval Superiority: At the Battle of Salamis, the Greek commander Themistocles lured the larger Persian fleet into narrow straits. The Greek triremes, which were sturdier and better suited for ramming, exploited the cramped conditions where the Persian ships could not maneuver effectively, leading to a decisive naval triumph.34
• Tactical Infantry Combat: At the Battle of Marathon, the Greeks utilized superior armor, swords, and long spears to defeat the Persian infantry. Later, at the Battle of Plataea, the disciplined Spartan and Tegean hoplites overwhelmed the Persian forces in close-formation combat.54
• Defensive Sacrifice: While the stand at Thermopylae could not be held indefinitely, it served as a critical holding operation that allowed the Greeks to organize their broader defense.6