In the beginning of the movie, when the mother is planning to decorate a house, and she says: "a seventeenth century piano would look great right over there." Wait a minute! 17th century pianos didn't exist! They weren't invented yet!
Sorry, but Pianos were invented in the 17 century. Actually the first piano was invented by "Bartolomeo Cristofori in...1699", which would be the late 17th century. To make a replica of this very old piano would have been quite easy, but I doubt that they could have found one from the actual time period. *The quoted material was found at http://www.ptg.org/birkett/frame2.html