George Orwell comments on the concept of 'historical fact.'

From Looking Back on the Spanish War, (1943)

I know it is the fashion to say that most of recorded history is lies anyway. I am willing to believe that history is for the most part inaccurate and biased, but what is peculiar to our own age is the abandonment of the idea that history could be truthfully written. In the past, people deliberately lied, or they unconsciously colored what they wrote, or they struggled after the truth, well knowing that they must make many mistakes; but in each case they believed that "the facts" existed and were more or less discoverable. And in practice there was always a considerable body of fact which would have been agreed to by almost anyone. If you look up the history of the last war in, for instance, the Encyclopedia Britannica, you will find that a respectable amount of the material is drawn from German sources. A British and a German historian would disagree deeply on many things, even on fundamentals, but there would still be a body of, as it were, neutral fact on which neither would seriously challenge the other. It is just this common basis of agreement with its implication that human beings are all one species of animal, that totalitarianism destroys. Nazi theory indeed specifically denies that such a thing as "the truth" exists. There is, for instance, no such thing as "Science". There is only "German Science," "Jewish Science," etc. The implied objective of this line of thought is a nightmare world in which the Leader, or some ruling clique, controls not only the future but the past. If the Leader says of such and such an event, "It never happened" -- well, it never happened. If he says that two and two are five -- well two and two are five. This prospect frightens me much more than bombs -- and after our experiences of the last few years that is not such a frivolous statement.

-- George Orwell
Looking Back on the Spanish War, (1943)