The iconic battle to the death between the Greeks under the Spartan King Leonidas and Xerxes's Persian Imperial forces.

Leonidas led a force of 6,000 Greeks to halt the Persian advance at a narrow pass where the massive Persian numerical supremacy would count less. For three days Xerxes was held back, until the Greek traitor, Ephialtes, showed them a path into the mountains to out-flank the Greeks. Xerxes' personal bodyguard (often known as 'the immortals') brushed asside the force sent to block this pass, and by the time Leonidas sent reinforcements, he was encircled.

While most of the Greeks managed to withdraw, Leonidas and his Spartan bodyguard of 300 warriors, plus perhaps up to 1,000 others including the Helot slaves remained, and fought to the last. Although technically a Persian victory, it provided an example of Greek sacrifice and discipline which stiffened Greek resolve then, and still echos throughout classic and military thought today.