Zack Snyder’s dip into ancient Greek history in 300 focused on the Battle of Thermopylae, but the true story had a few details the movie left out or changed. 300 depicts the legendary Battle of Thermopylae, a decisive moment in the Greco-Persian War. The Battle of Thermopylae has long been the stuff of legend, and King Leonidas has become a worldwide symbol of bravery and courage. Leonidas stood against the invading Persian army, led by King Xerxes I, and though he met his demise there, he now lives on forever through history.

https://screenrant.com/300-movie-battle-of-thermopylae-true-story/