This is a post that pretty much sums up my ideas about the "true" histories of what happened in my universe.
They're basically non-existant.
My reasoning is this, and it's borrowed from the authors of a book called 1066 And All That: A Memorable History of England, Comprising All The Parts You Can Remember, Including 103 Good Things, 5 Bad Kings, and 2 Genuine Dates.
Early on in the book, they describe history in this way: "History is made up of all the parts you can remember. Any other history, not being memorable, defeats itself." Excuse the direct quotes, it's probably not completely accurate, but that's essentially it.
My point is this. It doesn't really matter what actually happened, unless somebody's going to find out. If they're going to find out, I don't need to know now. In fact, by deciding now, I might lose an opportunity to do something really cool that a player thought of.
What I do need to know, is what everybody thinks happened. If I don't know the perceived histories, I can't really play the NPC present. So don't look for lot of "this is what happened" in my work. Look deeper and you'll discover that probably that's only what mostly everybody thinks happened.