Final answer:
Leonidas was considered a national hero in Greece because of his role in the revolution. He led the famous 300 Spartans into battle against the Persians and became a symbol of heroism and resistance.
Step-by-step explanation:
The national hero in Greece because of his role in their revolution was Leonidas. He was the king of Sparta and led a small force of Greeks, including the renowned 300 Spartans, against the massive Persian army in the Battle of Thermopylae. Although they were ultimately defeated, Leonidas and his soldiers fought with great bravery and sacrifice, becoming symbols of heroism and resistance.