However, on the third day, a local resident named Ephialtes betrayed the Greeks by revealing a hidden path around the pass to the Persians. The Persians exploited this weakness and attacked the Spartans from behind.

The Spartans, known for their exceptional combat skills, were joined by several hundred Thespians and Thebans. Together, they formed a small but determined force to defend the pass.

The battle ultimately led to the Greek victory at the Battle of Plataea, where the Persian army was defeated, and the invasion of Greece was repelled.

For three days, the Spartans and their allies fought valiantly, holding off the Persian army. The Spartans' superior training and combat tactics allowed them to inflict heavy casualties on the Persians.