1. Geographic Advantage: The Greeks had the advantage of fighting on their home turf. The mountainous terrain of Greece made it difficult for the Persian cavalry to maneuver effectively, while the narrow mountain passes allowed the Greeks to use their hoplite phalanx formation to great effect.
2. Unity: The Greek city-states were able to set aside their differences and unite against the common Persian threat. This unity was largely due to the efforts of the Athenian statesman Themistocles, who convinced the other city-states to form an alliance against Persia.
3. Naval Power: The Greek navy was superior to the Persian navy, thanks in large part to the Athenian trireme, a fast and maneuverable warship. The Greek navy was able to defeat the Persian fleet at the Battle of Salamis, which was a turning point in the war.
4. Leadership: The Greeks were led by some of the greatest military commanders in history, including Miltiades, Themistocles, and Leonidas. These leaders were able to inspire their troops and develop effective strategies for defeating the Persians.
5. Military Tactics: The Greeks employed several effective military tactics, such as the hoplite phalanx formation and the use of terrain to their advantage. These tactics allowed the Greeks to defeat the larger Persian armies.
6. Persian Overconfidence: The Persians were overconfident and underestimated the strength of the Greeks. They also made several strategic mistakes, such as dividing their forces and failing to properly scout the terrain.
In conclusion, the Greek victory over the Persians was the result of a combination of factors, including geographic advantage, unity, naval power, leadership, military tactics, and Persian overconfidence.