Leonidas, one of the two kings in the Spartan diarchy, died fighting the Persian Invasion at Thermopylae. He had a force of three hundred Spartans, augmented by a thousand or so soldiers from his allies. He had sent the main part of his force in retreat, and was holding the pass at Thermopylae in order to give the Athenians and the other Grecian states more time to prepare against the Persians.
