History of the Peloponnesian War

"The Lacedaemonians shall be confederates with the Athenians for fifty years. "If any enemy invade the territory of the Lacedaemonians and do the Lacedaemonians any harm, the Athenians shall aid the Lacedaemonians against them in the strongest manner they can possibly; but if the enemy, after he hath spoiled the country, shall be gone away, then that city shall be held as enemy both to the Lacedaemonians and to the Athenians and shall be warred upon by them both; and both cities shall again lay down the war jointly; and this is to be done justly, readily, and sincerely.

"And if any enemy shall invade the territories of the Athenians and do the Athenians any harm, then the Lacedaemonians shall aid the Athenians against them in the strongest manner they can possibly; but if the enemy, after he hath spoiled the country, shall be gone away, then shall that city be held for enemy both to the Lacedaemonians and to the Athenians and shall be warred upon by both;