History of the Peloponnesian War

And I remember yet that from the very beginning of this war and so on till the end it was uttered by many that it should be of thrice nine years' continuance.

And for the time thereof I lived in my strength and applied my mind to gain an accurate knowledge of the same. It happened also that I was banished my country for twenty years, after my charge at Amphipolis; whereby being present at the affairs of both, and especially of the Lacedaemonians by reason of my exile, I could at leisure the better learn the truth of all that passed.

The quarrels, therefore, and perturbations of the peace, after those ten years, and that which followed, according as from time to time the war was carried, I will now pursue.