an Entity references as follows:
Wilhelm Backhaus ('Bachaus' on some record labels) (26 March 1884 – 5 July 1969) was a German pianist and pedagogue. He was particularly well known for his interpretations of Beethoven and romantic music such as that by Brahms. He was also much admired as a chamber musician. He seems to have favoured Bösendorfer pianos as he can be seen playing this instrument in commercial videos with Karl Böhm and Hans Knappertsbusch conducting. Also see his original photograph and handwritten letter of appreciation of the Bösendorfer in their main showroom in Vienna.