Who led the Greek forces at Thermopylae?

Who led the Greek forces at Thermopylae? King Leonidas of Sparta led them. In 480 BC, Leonidas commanded a Greek coalition defending the narrow pass of Thermopylae against the invading Persian army of Xerxes I. The force included about 300 Spartan citizens, but the famous Spartan contingent was only part of a larger army that initially numbered roughly 7,000 men from several Greek city-states.

Leonidas was one of Sparta’s two hereditary kings, a political system designed to divide royal authority between two ruling families. He selected soldiers who had living sons, reportedly because he understood that the mission was exceptionally dangerous. The Greeks used the narrow terrain and a defensive wall to prevent the much larger Persian army from deploying its full strength.

After a local man named Ephialtes revealed a mountain path around the pass, Leonidas dismissed most of the Greek force. He remained with the 300 Spartans and other defenders, including Thespians and Thebans, to delay the Persians. Leonidas died during the final fighting. Themistocles, sometimes confused with the land commander, led the Greek naval strategy at nearby Artemisium and later Salamis.