Spartan King Leonidas knew that the mission to defeat the Persians was a perilous one. Leonidas along with 300 other Spartans fought until the last man. | Odyssey - Ancient History

Battle of Thermopylae 480 BC: The Day 300 Spartans Refused to Break King Leonidas and his 300 Spartans—backed by 7,000 Greek allies—held the narrow Thermopylae pass for three days against Xerxes I's massive Persian invasion of 100,000-300,000 troops, using unbreakable phalanx discipline and terrain to inflict devastating losses before a traitor's betrayal sealed their heroic last stand. Terrain as the Ultimate Ally The coastal bottleneck—just wide enough for two wagons—neutralized Persian number