History of the Peloponnesian War

And the best of the land was always the most subject to these changes of inhabitants; as that which is now called Thessaly, and Boeotia, and the greatest part of the Peloponnese, (except Arcadia,) and of the rest of Greece whatsoever was most fertile.

For through the goodness of the land, both the power of some particular men growing greater caused factions among them, whereby they were ruined; and withal they were more exposed to the plots of strangers.

Attica, at any rate, having through the poverty of the soil been for the longest period free from factions, was always inhabited by the same people.

And this which follows is not the least evidence of my assertion, that it was owing to its migrations that Greece did not equally increase in other parts. For such as by war or sedi tion were driven out of the rest of Greece, the most powerful of them retired to Athens, as to a place of security; and becoming citizens at a very early period, made the city still greater in the number of inhabitants; so that afterwards they even sent out colonies into Ionia, as Attica itself was not able to contain them.