History of the Peloponnesian War
Thucydides
Thucydides. The history of the Peloponnesian War, Volume 1-2. Dale, Henry, translator. London: Heinemann and Henry G. Bohn, 1851-1852.
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.