The popularity of Cimon at last declined, and he suffered ostracism, as had Aristides and Themistocles before him. His loss of public favor came about in this manner. In the year 464 B.C., a terrible earthquake destroyed a large portion of Sparta. In the panic of the appalling disaster the Spartans were led to believe that the evil had befallen them as a punishment for their recent violation of the Temple of Poseidon, from which some Helots who had fled to the sanctuary for refuge had been torn. The Helots, on their part, were quick to interpret the event as an intervention of the gods in their behalf, and as an unmistakable signal for their uprising. Everywhere they flew to arms, and, being joined by some of the Perioeci, furiously attacked their masters. The Spartans, after maintaining the bitter struggle for several years, finding themselves unable to reduce their former slaves to submission, were forced to ask aid of the other Grecian states. The great Athenian statesman Pericles implored his countrymen not to lend themselves to the building up of the power of their rival. But the aristocratic Cimon, who had always entertained the most friendly feelings for the Spartans, exhorted the Athenians to put aside all sentiments of enmity or jealousy, and to extend succor to their kinsmen. "Let not Greece," said he, "be lamed, and thus Athens herself be deprived of her yokefellow." The assembly voted as he advised, and so the Athenian forces fought for some time side by side with the Lacedæmonians. But the Spartans were distrustful of their Athenian allies, and fearing they might pass over to the side of the Helots, they dismissed them. The discourtesy of the act aroused the most bitter resentment at Athens. The party of Pericles took advantage of the exasperated feelings of the people to effect some important changes in the constitution in favor of the people, which made it almost purely democratical in character, and to secure the exercise of the ostracism against Cimon as the leader of the aristocratical party and the friend of Sparta (459 B.C.). THE AGE OF PERICLES (459-431 B.C.). GENERAL FEATURES OF THE AGE.--Under the inspiration of Pericles, the Athenian state now entered upon the most brilliant period of its history. The epoch embraces less than the lifetime of a single generation, yet its influence upon the civilization of the world can hardly be overrated. During this short period Athens gave birth to more great men--poets, artists, statesmen, and philosophers--than all the world besides has produced in any period of equal length. [Illustration: PERICLES.] Among all the great men of this age, Pericles stood pre-eminent. Such was the impression he left upon the period in which he lived, that it is called after him the Periclean Age. Yet Pericles' authority was simply that which talent and character justly confer. He ruled, as Plutarch says, by the art of persuasion.