The Achæan peoples of the heroic age, when they were driven by the invading Dorians from Sparta, Messenia, Argos and Corinth, took refuge in the northern part of the Peloponnesus and there founded the Achæan people of the historical period. The district in which they settled measures only about sixty-five English miles from east to west along the coast of the Corinthian gulf, and from twelve to twenty miles from north to south. It is cut off from the rest of the Peloponnesus by a range of lofty mountains which cannot in any part be crossed without difficulty. From this mountain range many ridges run northward, dividing the country into narrow valleys[250]. The past history of the Achæans and the character of their territory made them well suited for a federal form of government; that is to say, for having a single government for some purposes and many governments for other purposes. They were impelled towards union by their common Achæan race, by common experience of conquest by the Dorians, and by the certainty that, if an independent state were formed in each little valley, none of them would be large enough to be of any importance in Greece: but at the same time some sort of separate government in each valley was natural in a country where communications were so much interrupted by mountains. It is said that they lived for a time under a single government only--the kingly government of the descendants of their hero Orestes: but at some very early period each of the valleys must have acquired some sort of independence, since, on the abolition of the kingly government, at a time too early to be known to history, the separate cantons or cities acted for themselves and voluntarily joined together in a confederation, adopting at the same time institutions of a popular character. They acquired such a reputation for just government and good faith in their dealings that after the battle of Leuctra in 371 B.C. they were singled out from all the Greek states to act as arbitrators, on some points which were disputed, between the victorious Thebans and the defeated Spartans: and Polybius believed they had acted in the same capacity at a much earlier date in the affairs of Croton and Sybaris, two states which had been founded in southern Italy by colonists from Achaia[251]. For centuries they lived on, somewhat isolated from the rest of Greece and little noticed by Greek writers, but maintaining their union and their system of government. Even in the days of Philip of Macedonia and his son Alexander the Great they were left unmolested: but, after Alexander's death, some of the ambitious princes who contended for power in Greece and Macedonia contrived to sow discord among their cities: they were consequently unable to defend themselves, and some of the cities were occupied by Macedonian garrisons, while others were put under the rule of tyrants. The gradual destruction of the league which was thus brought about must, from what