By the time that Plato’s Republic was published (according to Scott Buchanan in the Introduction to The Portable Plato), Plato seems to have concurred with his rival, Isocrates, that the Greek city-states should formally agree (in the event of war between or among whatever states) upon certain “civilized” rules for the conduct of warfare. A prelude to the fixing of such an agreement seems to be Plato’s intent in his discussion of the conduct of the Guardians (Book V) in the event of internecine discord. In the Notes to The Republic of Plato, Francis MacDonald Cornford notes that, although Plato “expresses no humanitarian sympathy extending beyond the borders of Hellas,” Plato is one of the earliest writers to stand for a rule of international law between independent states. Plato, Isocrates, and other thinkers were fully aware of the narrow escape from subjugation the Greeks had been granted at the close of the Persian war in 479 b.c.—a war waged against Persia by an alliance of Hellenic city-states including Athens and Sparta, who not many years later would be at war against each other. These thinkers had been nurtured on stories of the Persians’ barbarity during the conduct of that war, barbarity practiced upon heroic Greek warriors such as the Spartan Leonidas.
According to the ancient Greek historian Herodotus in The History of Herodotus, Leonidas was in command of the now famous 300 Spartans who were sent, in advance of the main Spartan body of troops, to engage the Persian horde in order to arrest and defeat its intended invasion of Greece. The Spartan troops of only 300 men at arms were augmented by troops sent by several other city-states who seemed determined to engage the Persian forces, but Leonidas had picked up and accompanied the delegation of troops from Thebes, because the Thebans had already hinted that they might desert the Greek alliance and unite themselves with the Persians. In order to shore up the flagging hopes of their allies, therefore, the Spartan advance guard made camp in a narrow mountain pass at a place now made famous by the battle fought there—Thermopylae (the Hot Gates).
The reason why Leonidas appeared with only a token force was that Sparta was at that time celebrating a religious festival; the reason why the other Greek forces were so scanty was that their cities were celebrating their Olympic games. Neither Sparta, famous for the quality of her fighting men, nor her allies thought that the battle of Thermopylae would be engaged as soon as it was, so the matter stood and there was nothing to be done about it: The Greek forces were hopelessly outnumbered, the Persian forces were upon them and in command of the pass through which they were penetrating the country, and there was Leonidas with his 300 Spartans camped in front of the enemy’s first wave.
Xerxes, the tyrannical ruler of the Persians and their huge conglomerate of allies, was—like many tyrants of his time and later—an unstable and arrogant person. Earlier in the war, having enthroned himself upon a vantage point overlooking his entire war host, he had alternately laughed at the earthly military might he saw displayed before him and then wept at their mortal mutability and evanescence. At any rate, Xerxes the tyrant was resolved to tolerate no insolence from the effete and intellectual Greeks who called him a barbarian, and the appearance of a mere 300 Spartans to engage his host in hand-to-hand combat must have seemed insolent in the extreme.
Xerxes was at the same time angered and intrigued by these men called Spartans, so he had the Greek ramparts scouted out. On the day that Xerxes sent his scout to reconnoiter the Greek camp, the Spartans had been assigned as perimeter guards outside the camp’s ramparts. There, Xerxes’ scout saw them, counted them, and then returned to report to his master what he had seen.
And this is what the Persian scout saw at the place of the Hot Gates so long ago: He saw the Spartan warriors engaged in oiling their bodies and dressing their long hair outside the ramparts of Thermopylae. He saw others of the Spartans exercising at gymnastics and swordplay and general forms of leisure activity. He saw the Spartan warriors sunning themselves. And he saw that the Spartans did not seem to consider his presence worthy of much notice.
