The writing of history is closer to fiction than any fiction. It is always biased, tendentious, subjective, manipulative, political, and propagandistic.
There is, however, one characteristic that distinguishes the American way of writing history from everybody else’s. When I read history books published in Spain, the UK, Ukraine, Germany, Russia, or Latin America, I am likely to find any number of lies and mistakes, yet all of these books will have one thing in common: every historic moment they discuss will feature a number of players who will interact with each other in a variety of ways based on their own, often conflicting interests.
American history writing only features a single player, godlike in its omnipotence and loneliness. Each history book discusses this character’s interaction with itself. That lonely, all-powerful player is, of course, the United States. The possibility that there might be other players on the world arena, with an agency and needs of their own never even registers.
So if you pick up, say, a history of Guatemala or World War I or the USSR or anything else written by an American, you will discover that the book isn’t really about Guatemala or World War I. It will be about the US creating and acting upon Guatemala, etc.
I’m not sure if there are any American medieval historians of note, but if they do, God, how they must suffer because of the incapacity to stick the US into every sentence.