THE BATTLE OF THERMOPYLAE is one of the signal symbolic events in the history of Western civilization. Athens and Jerusalem are the standard shorthands for the West's cultural headwaters, but at Thermopylae, Sparta, that historical mystery of a superpower, played a role for which perhaps she, and only she, was suited.

The story is familiar to anyone with a passing knowledge in military or classical history. Xerxes the Great of Persia set about incorporating Greece into his empire with an army Herodotus estimated at 5 million, half under arms. Leonidas of Sparta, hampered by obscure religious and political considerations, was able to take only 300 hand-picked soldiers as the spearhead of an allied force to meet the Persians at Thermopylae--"the Hot Gates," a narrow pass where the Persian superiority in maneuver and numbers would be negated. The Spartans and their allies held off the Persians until a traitor named Ephialtes of Trachis revealed a secret path around their rear which allowed the Spartans to be encircled and defeated. When Leonidas got word of this, he released his allies, but he and his 300 men, joined by 700 brave Thespians, fought to the death, in willing submission to the Spartan law of no retreat, no surrender.

Their martial prowess, professionalism, sangfroid (see Housman's famous line, "The Spartans on the sea-wet rock sat down and combed their hair."), and absolute sense of honor unto death, were shocking to the Persians and became more than an epic war story: Historians from Herodotus, through Plutarch, and stretching all the way to Victor Davis Hanson some 25 centuries later, have seen in this instance of a tiny force composed of free men dealing horrible destruction to a larger, slave military, the very essence of the conflict between East and West.

Greece was the only location in the classical world in which the flame of liberty burned. A Persian victory would have snuffed out the Greek concept of freedom under the law, imposing a highly centralized god-king system known to past generations as Oriental Despotism. The free Spartans, in this telling, not only fought better as free men fighting for their liberty, but their sacrifice helped preserve the notions and institutions which blossomed into the glorious civilization eventually built on Greek foundations.

FOR THE HEIRS OF THIS SACRIFICE some two millennia on, this story does not sit entirely well. The Spartans, in their way, are as alien to us as the Ancient Egyptians, and due to the fact that they considered it forbidden to transcribe any of their laws, we know considerably less about them than the charmingly literal-minded folk on the Nile, who managed to combine magical thinking and the some of the greatest feats of practical engineering the world has ever seen.

Much of what we do know about the Spartans isn't attractive to modern eyes. Their entire society was geared toward producing and maintaining a professional, standing army, and it did so principally by killing infant boys who seemed weak and brutalizing the surviving children until they were fearless, skillful dealers of death.