Jazz critic Gary Giddins on Louis Armstrong (from a Ken Burns interview):
What does he bring to this music that has not previously existed?
First of all, he establishes, almost single-handedly, that jazz is going to be a soloist's art, not an ensemble music.
Number two, he affirms for all time that a fundamental basis for this music is going to be a blues tonality, which is going to be as fundamental to jazz as a tempered scale is to Western music. It's the blood, it's the life of the music.
Third, and most significant, and I think this is maybe THE great innovation in American music, and it's the most astonishing to contemplate; Armstrong invented what, for lack of a more specific phrase, we call swing. He created modern Time.
The music that Armstrong improvised in 1928 excites us today. And if that's not classical music, I don't know what is.
What an amazing force of nature Armstrong was.