History of the Peloponnesian War

"Now, if we were wise, we ought rather to call in confederates and undergo dangers for the winning of somewhat that is none of ours than for the impairing of what we already have; and to believe that nothing so much destroys a city as sedition, and that Sicily, though we the inhabitants thereof be insidiated by the Athenians as one body, is nevertheless city against city in sedition within itself.

In contemplation whereof, we ought, man with man and city with city, to return again into amity; and with one consent to endeavour the safety of all Sicily: and not to have this conceit, that though the Dorians be the Athenians' enemies, yet the Chalcideans are safe, as being of the race of the Ionians.