History of the Peloponnesian War

The quarrel between us and them arose at first from this, that when we had built Plataea last of all the cities of Boeotia, together with some other places which, having driven out the promiscuous nations, we had then in our dominion, they would not (as was ordained at first) allow us to be their leaders; but being the only men of all the Boeotians that transgressed the common ordinance of the country when they should have been compelled to their duty, they turned unto the Athenians and together with them did us many evils, for which they likewise suffered as many from us.