J.S.Bach
I ought to note in passing an innovation of Bach's which was, apparently, entirely his own. He was the first keyboard player to use all 10 fingers. Prior to him, the thumbs were almost never used unless needed to stretch to an interval you couldn't reach with the other fingers. One played with the fingers straight (the fault which piano teachers are constantly correcting since Bach's time) and there were many fingerings, like crossing 2 over 3, or 4 over 5, etc., which seem very wierd today, but were what you had to do if you only used the 8 fingers. Bach, according to contemporary witnesses, not only played with his thumbs but with his fingers curved and without lifting them very high off the keys. He taught his sons and his students this method and it has become standard. By way of contrast, try playing Buxtehude or Sweelinck or one of the older generation composers in the old manner, without the thumbs. Also, although old J.S. wrote some organ music which is playable only by virtuosi, he did not, like Rachmaninoff, write music requiring huge hands, making huge problems for musicians like me who have small hands; I know of only 2 places in the organ literature of Bach which stretch more than an octave.
