History of the Peloponnesian War

For the goodness of the land increasing the power of some particular men both caused seditions, whereby they were ruined at home, and withal made them more obnoxious to the insidiation of strangers.

From hence it is that Attica, from great antiquity for the sterility of the soil free from seditions, hath been inhabited ever by the same people.

And it is none of the least evidences of what I have said that Greece, by reason of sundry transplantations, hath not in other parts received the like augmentation. For such as by war or sedition were driven out of other places, the most potent of them, as to a place of stability, retired themselves to Athens; where receiving the freedom of the city, they long since so increased the same in number of people, as, Attica being incapable of them itself, they sent out colonies into Ionia.