Did you know that Franz Liszt himself dared to add additions and ornamentation to the great Beethoven Himself?! Blasphamous piece of s***.
He stopped doing that later. It wasn't a big deal then. If it hadn't been for Mendelssohn, for example, Bach's position in musical history might have been quite different, and yet the performance of the St. Matthew Passion he organised would have been seen as sacrilege today. There were bits chopped off and changed everywhere. That was their way of honouring the music that had been written earlier: adapting it to the present.
I always though that it was Mendelssohn who 'ressurected' Bach but that wheel of compsoers that Berhnard posted last year confused me. He was on the top of the circle yet an unkown?