Who was a king from Sparta who led soldiers into battle at thermopylae?

King Leonidas I was the Spartan king who famously led his soldiers into battle at the Battle of Thermopylae in 480 BC. He is renowned for his courageous stand against the vastly superior Persian army, demonstrating exceptional bravery and tactical skill. Leonidas and his small force, including 300 Spartans, fought valiantly, ultimately sacrificing their lives to delay the Persian advance and inspire Greek unity against the invaders. His legacy is celebrated as a symbol of courage and resistance.