Marathon. In 490 B.C.E. at Marathon, on the northern coast of Attica, the Athenians repulsed an army of Persians intent on gaining their submission and on reimposing on them the rule of the tyrant Hippias, who had been forced from Athens twenty-one years before. That Athens could block both the Persians and the return of tyranny gave a tremendous morale boost to its still budding democratic constitution. The Athenians had adopted it in 506, but they still had concerns about those who might aim at tyranny. That they won this victory without the help of the Spartans, the foremost warriors of the Greek world and the leaders of the Hellenic League, helped establish the Athenians' own claim to be an effective, independent fighting force. Athens was clearly the leading city among the Ionian Greeks, who lived on the central islands...