How did the Battle of Thermopylae affect Greece?

The Persians invaded deeper into Greece.
Greece gained territory from the Persians.
Greece set up an alliance with the Persians.
The Persians gained total control of Greece.

The significance of the battle for Western Civilization

While the Battle of Thermopylae was technically a defeat for the Greeks, it was also a victory in the long run because it marked the beginning of several important Greek victories against the Persians and boosted the morale of all the Greek city-states.

Explanation:

study of past cultures