History of the Peloponnesian War

For there is no disgrace in kinsmen giving way to kinsmen, a Dorian to a Dorian or a Chalcidian to men of the same race, since we are, in a word, neighbours and together are dwellers in a single land encircled by the sea and are called by a single name, Siceliots. We shall go to war, no doubt, whenever occasion arises—yes, and we shall make peace again by taking common counsel among ourselves;

but when alien peoples invade us, we shall always act in concert, if we are prudent, and repel them, seeing that any injury suffered by one of us brings danger to us all; but never henceforth shall we ask outsiders to intervene, either as allies or as mediators.