Answer
The Battle of Thermopylae lasted three days, from August 11-13, 480 BC. The Persian army, led by Xerxes I, vastly outnumbered the Greek forces led by King Leonidas of Sparta. Despite their numerical disadvantage, the Greeks held off the Persians for three days before being betrayed and ultimately defeated. The battle remains a legendary example of courage and sacrifice in the face of overwhelming odds.