Thucydides,
History of the Peloponnesian War…
“ We shall go to war again, I suppose, when the time comes, and again make peace among ourselves by means of future congresses; but the foreign invader, if we are wise, will always find us united against him, since the hurt of one is the danger of all; and we shall never, in future, invite into the island either allies or mediators. By so acting we shall at the present moment do for Sicily a double service, ridding her at once of the Athenians, and of civil war, and in future shall live in freedom at home, and be less menaced from abroad. ”
