Who were the most important composers in history?

Answer 1

A highly subjective question requiring such an answer. But since music evolved and still does all, composers, to a greater or lesser extent are 'most important'. Just three examples of the impossibility of a simple answer - [1] Monteverdi - is he any less than Beethoven in the bigger picture? - how would he have composed for the piano if it existed in his day? [2] The French Horn. How would composers scoring for it without valves [hand horn] have dealt with it with valves? - the old composer had to allow time for the player to change the crook, the modern composer knew a split second movement of the finger on the valve did the same to enable the player to [for example] change Key etc. [3] Patronage. A composer in the employment of a 'Patron' composed what the Patron wanted - the style and kind of music required. The composer had very little lee-way. Indeed much of their music was like our 'canned' music in shops - purely back-ground. Even early Opera was incidental until a 'favourite' started to sing. Without the constraints of patronage Beethoven composer music for the piano that was factually impossible to play properly on the pianos of his day.