History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
And the endeavour to ascertain these facts was a laborious task, because those who were eye-witnesses of the several events did not give the same reports about the same things, but reports varying according to their championship of one side or the other, or according to their recollection.
And it may well be that the absence of the fabulous from my narrative will seem less pleasing to the ear; but whoever shall wish to have a clear view both of the events which have happened and of those which will some day, in all human probability, happen again in the same or a similar way—for these to adjudge my history profitable will be enough for me. And, indeed, it has been composed, not as a prize-essay to be heard for the moment, but as a possession for all time.