This is a major problem in a lot of history writing. Years ago I interviewed my grandfather, who lived in a city in southern Russia during the 1917 revolution and a short-lived British occupation. I wrote his biography as my undergraduate thesis (yeah, there used to be such a thing, in the days before you could get a degree in pop music). Before interviewing him, I practically lived in the New York City Public Library for 3 months researching and reading every book and document I could find about that time and place, from dusty old volumes to current texts and articles. Then I interviewed my grandfather over a period of a month. Some of the things he said didn't match the historical records. I figured maybe age had clouded his memory. So I brought up the subject in different ways at various times over the month. He was always consistent in his responses. When I mentioned the books - at least a dozen books listed a different sequence of events than what he had told me - he cursed and said "Who are you going to believe, some ivory tower academic or someone who lived through it?" He backed up his account of events by linking them with other things that had happened, all of which made sense. And his recollections seemed crystal-clear.
I then went back and paid close attention to the references in all these books. I realized that if you did try to link the various events my gradfather told me about, every one of these books contradicted themselves. It turns out that a British officer had written a memoir of his experiences at the time, and that was then referenced by a historian, and his work was in turn referenced by later historians. And so on. Most likely it was the British officer's memory that was clouded, and everyone after him accepted his words as fact. Unfortunately the Russian histories were totally unreliable, written during the Soviet era, whereas many of the actual events involved were very unflattering to the communists. No one had made the effort to check the facts and find another independent reference. We're talking a major event here: the day the Red Army pulled into town.
Recently I've been working on another project which involves historical research in southern China. The exact same problem is coming up: a single memoir based on hearsay becomes the (hidden) reference for all subsequent scholarship. The Chinese historical records are patchy and mainly limited to censuses and court records, not events, so all we know of certain people and events in that part of China is from foreign mercenaries who may have been motivated to, shall we say, romanticize their own exploits. Yet these are cited as cold, hard facts, and then re-cited and then the later publications are re-referenced by everyone else since. It gets even worse! In the 1930s a British historian was contracted by a publisher to write a "popular history" of the region, and he jazzed it up with completely made-up "facts", things he could never have really known. He even acknowledged in later interviews that he had "embellished" his history. Yet his text is cited at face value as a reference in later scholarly texts. I found a historian at one of the local universities who is an expert on this particular topic, and he confirmed that it's very common in historical writing that this sort of incestuous cross-referencing occurs.
So never trust what you read in a history book. Do your own research.
