The famous Spartan king at the Battle of Thermopylae was King Leonidas I. He reigned during the early 5th century BC and is best remembered for his leadership during this pivotal confrontation against the invading Persian forces led by King Xerxes in 480 BC. Despite being vastly outnumbered, Leonidas and his 300 Spartan warriors exemplified bravery and heroism, fiercely defending their position at the narrow pass of Thermopylae. Their legendary stand became a symbol of courage and sacrifice, inspiring future generations. Leonidas's tactical decisions and the valor displayed by his men have made Thermopylae a renowned event in military history and a focal point in discussions about the ideals of honor and duty.