Answer
Leonidas I, the legendary Spartan king, perished on August 11, 480 BC, during the Battle of Thermopylae. Leading a small force of 300 Spartans and 700 Thespians, he held off the massive Persian army for three days, allowing the Greek city-states to prepare for the upcoming invasion. Leonidas' heroic stand and ultimate sacrifice became a symbol of Greek courage and determination in the face of overwhelming odds.