Harry Potter & Mr Norrell

I was desperately trying to find a way to incorporate Harry Potter into my paper topic and I thought about something that was similar between the two novels (although I won't be writing about it...because I think I'm going to write about the importance of prophechy in each book), but I was also thinking about each author's use of alternate history. It obviously pops up over and over in Strange & Norrell, but in Half Blood Prince, when the two ministers (muggle and minister of magic) meet at the beginning, the "other" minister talks to Fudge about the terrible things that have been happening on his end...and Fudge points out that they have both been experiencing the same events. I know it is not strictly an alternate history, but it is a parallel universe i guess, I just liked that part of the novel, thought i'd throw that out.