Shakespeare's Kings - John Juilus Norwich

I was enjoying this, and taking copious notes, until I stumbled on the bizarre statement in Henry V that Nym had 'been imported from the Merry Wives of Windsor', which displayed such a stunning lack of knowledge about the background of the plays and dates that it quite knocked me sideways. Then noticed another weirdo-potato statement that in Richard II, that Wiltshire 'appears nowhere in Shakespeare's play'... apart from being a character, of course. At this point I stopped reading because I couldn't trust the book any more and didn't want to perpetuate any inaccuracies by taking them as fact. A shame, because it had some humour.