It's been called "America's Classical Music". It's been called "The Sound Of Surprise". The first jazz record ever recorded was on February 26, 1917 by the Original Dixieland Jass Band. It was "Livery Stable Blues" on one side and "Dixieland Jass Band One-Step" on the other.
Listening to it now, the music seems so dated and simple. The tunes consisted of group playing with no individual soloing.
https://www.youtube.com/watch?v=5WojNaU4-kI
Louis Armstrong would change everything. He would make the individual solo front and centre in his performances and, in turn, pressure other jazz musicians to follow suit.
https://www.youtube.com/watch?v=pXHdqTVC3cA
Many jazz musicians, to this day, cite Louis Armstrong as one of the most important figures in the history of jazz.