On Memory, History, and Truth

Memory is a funny thing. When people recount something tend to exaggerate, if nothing else to make a good story of that event. I have to wonder how much of that has gone into history books. I mean, eye-witnesses are still flawed human beings and History isn't an exact science. So how flexible is history, if everything recorded is at the discretion of those who write it down? Surely a few details can be tweaked to add colour and flavour to the telling, but how much freedom should they have? How much fact can be sacrificed without sacrificing the truth? Nothing's ever going to be remembered exactly as it was. Those things will be enlarged or down-sized depending on their opinions of those things, those events, people and places of the past, and people will remember the event for the story, how it remained imprinted in their minds. In an historical battle, if books say so-and-so killed this many people, when really he only killed a couple, is it really going to matter in the long run? The point is we know who won the battle and where it got us, and we got a good story out of it too, from the worm's-eye view. So there's no problem, right? But then I think of memoir writers and autobiographies, and I think: those people couldn't have possibly remembered every detail from their past, exactly what people said and how. There's no way, unless they were thinking "I'm going to write about this 30 years from now, so I'd better pay attention". Surely they stretched the truth a little. Otherwise, only people with photographic memories can write autobiographies and memoir. At any rate, perhaps it's the memory matters more than the details.