Underestimating the Greeks: The Persian commanders underestimated the military prowess and determination of the Greek city-states. They viewed the Greeks as inferior and believed their superior numbers would easily overcome them. This underestimation led to strategic mistakes and a failure to adequately prepare for the Greek resistance.
Decentralized Command: The Persian army was not under a single unified command. Instead, it consisted of various contingents from different satrapies, each led by its local commander. This decentralized command structure resulted in poor coordination, communication issues, and a lack of cohesive strategy among the Persian forces.
Lack of Naval Superiority: The Persian Navy was not as powerful as the Greek navy. The Greeks had superior naval tactics and seafaring skills, which allowed them to effectively block the Persian fleet from supporting their land forces and cut off their supply lines.
Terrain and Geography: The Greeks were able to exploit the favorable terrain and geography to their advantage. They used mountain passes, narrow straits, and other geographical features to hinder the movement and supply of the massive Persian army.
Greek Unity and Leadership: The Greek city-states, despite their rivalries, were able to unite against a common threat and overcome their differences. The leadership provided by figures like Themistocles and Leonidas inspired and motivated the Greek forces to fight with exceptional valor and courage.
Lack of Flexibility and Adaptability: The Persians were slow to adapt to the changing circumstances and strategies of the Greeks. Their rigid military tactics and inflexible command structure prevented them from effectively countering the Greeks' more agile and flexible approach.
Defeats at Thermopylae and Salamis: The Persian defeats at the battles of Thermopylae and Salamis were significant turning points in the war. The heroic stand of the 300 Spartans at Thermopylae inspired the Greek forces and demoralized the Persians. The naval victory at Salamis shattered Persian hopes of conquering Greece through naval dominance.