Overthrow and Revolution
In 514 B.C. the tyrant Hipparchos was stabbed to death. The murder, actually the result of a love feud, was quickly deemed a political act of assassination and the perpetrators, Harmodios and Aristogeiton, were proclaimed heroes and tyrannicides. Several years after the deed they were honored with statues set up in the middle of the Agora. Of the original bronze statues nothing remains but a small marble fragment of the inscribed base bearing the name of Harmodios and part of the honorary epigram.
The reign of the remaining tyrant, Hippias, became increasingly severe, as Aristotle records:
After this it began to come about that the tyranny was much harsher; for Hippias' numerous executions and sentences of exile in revenge for his brother led to his being suspicious of everybody and embittered. (Athenian Constitution 19.1)
One of the leading families in exile, the Alkmaeonidai, made several attempts to dislodge the tyrants. Herodotus regards them as more significant than the tyrannicides in bringing an end to the Peisistratid tyranny:
Indeed, in my judgement it was the Alkmaeonidai much more than Harmodios and Aristogeiton who liberated Athens; for the latter two by their murder of Hipparchos merely exasperated the remaining members of the clan, without in any way checking their despotism, while the Alkmaeonidai did, in plain fact, actually bring about the liberation. (History of Greece 6.123)
The liberation did not come easily. It took four years and several unsuccessful military encounters before the Alkmaeonidai, changing tactics, managed to bribe Apollo's oracle at Delphi to persuade the Spartans to help them oust the tyrants. For several decades the Spartans had enjoyed a reputation as the best warriors in Greece, and with the help of a Spartan army led by King Kleomenes the tyrants were thrown out in 510 B.C.
Almost immediately, factional strife among the large families broke out once again, pitting the Alkmaeonid leader Kleisthenes against a certain Isagoras. At first Isagoras had the upper hand, until Kleisthenes enlisted the support of the common people by proposing a new constitution. Isagoras then called in the Spartans again. Kleomenes expelled 700 Athenian families, who joined Kleisthenes in exile. When Kleomenes and Isagoras tried to rescind the new Kleisthenic constitution, however, the Athenian people rose up in arms against them, threw the Spartans out, and recalled Kleisthenes.
But the Council resisted, and the multitude banded together, so the forces of Kleomenes and Isagoras took refuge in the Acropolis, and the people invested it and laid siege to it for two days. On the third day they let Meomenes and his comrades go away under a truce, and sent for Kleisthenes and the other exiles to come back. The people having taken control of affairs, Kleisthenes was their leader and was head of the People. (Athenian Constitution 20.3.4)
These events, which took place between 508 and 507 B.C., culminated in the democratic form of government that we celebrate today.
The new democracy was called upon to defend itself immediately. King Kleomenes, angered at the outcome, returned with a large army in 507/6 B.C., allied with the Boiotians and the Chalkidians. A three-pronged attack was planned, but at the last minute objections by the Corinthians and the other Spartan king, Demaratos, led to the withdrawal of the Spartans. The Athenians fought and defeated both the Boiotians and Chalkidians on a single day. The credit for this great success was attributed by Herodotus to the new democracy:
Thus Athens went from strength to strength and proved, if proof were needed, how noble a thing freedom is, not in one respect only, but in all; for while they were oppressed under a despotic government, they had no better success in war than any of their neighbors, yet once the yoke was flung off, they proved the finest fighters in the world. (Herodotus, History of Greece 5.78)