Battle of Thermopylae

The Battle of Thermopylae was fought between an alliance of Greek city-states, led by King Leonidas of Sparta, and the Persian Empire of Xerxes I over the course of three days, during the second Persian invasion of Greece. It took place simultaneously with the naval battle at Artemisium, in August or September 480 BC, at the narrow coastal pass of Thermopylae ("The Hot Gates"). The Persian invasion was a delayed response to the defeat of the first Persian invasion of Greece, which had been ended by the Athenian victory at the Battle of Marathon in 490 BC. Xerxes had amassed a huge army and navy, and set out to conquer all of Greece. The Athenian general Themistocles had proposed that the allied Greeks block the advance of the Persian army at the pass of Thermopylae, and simultaneously block the Persian navy at the Straits of Artemisium.

A Greek force of approximately 7,000 men marched north to block the pass in the middle of 480 BC. The Persian army, alleged by the ancient sources to have numbered over one million, but today considered to have been much smaller (various figures are given by scholars, ranging between about 100,000 and 150,000),[8][9] arrived at the pass in late August or early September. The vastly outnumbered Greeks held off the Persians for seven days (including three of battle) before the rear-guard was annihilated in one of history's most famous last stands. During two full days of battle, the small force led by Leonidas blocked the only road by which the massive Persian army could pass. After the second day, a local resident named Ephialtes betrayed the Greeks by revealing that a small path led behind the Greek lines. Leonidas, aware that his force was being outflanked, dismissed the bulk of the Greek army and remained to guard their retreat with 300 Spartans, 700 Thespians, 400 Thebans, fighting to the death.