History is bunk - Henry Ford.

It's a truism that history is written by the victors, and you need to bear that in mind when judging what you read about what has happened in the past.  I thought of this recently when the story broke about the site of Richard III's grave being sought underneath a car park in Leicester.  There is now considerable doubt whether Richard was really the hunchback monster he was portrayed as by his Tudor conquerors - and Shakespeare.  And then there is the story of a two thousand or so year old poem which has been discovered and recently translated which suggests that the Roman emperor Nero and his wife Poppaea may not have been as black as history has painted them.  So always keep that pinch of salt handy.