The musical and cultural revolution that brought about Jazz was a direct result of African-Americans pursuing careers in the arts following the United States civil war. As slaves African-Americans has learned few European cultural traditions. With more freedom to pursue careers in the arts and bringing African artistic traditions to their work, African-Americans changed music and dance, not only in the U.S., but all over the world. For after the war, African American dancers and musicians created work that was not similar by hundreds of years of musical and dance traditions brought from the peasant villages of Europe.
The music of Europe had a more base structure. European music through the nineteenth century was melodically based, with a square or waltz rhythmic structure. Differently, much African music has an organization which is based around rhythm and accent, rhythms and accents that may actually shift and move in relation to each other as the music progresses. The big change that took place in music rhythmically was the shift away from the rhythmic structure. African musical tradition tends to count towards the accented beat so that an African may count 2 on the same beat a European would count 1. It is typical of West African music to have rhythms of different lengths overlapping each other, creating shifting accents, sort of like a mix. Which is to say that by the late 1920's African-American Jazz music had developed a tradition where musicians put a strong rhythmic accent on "2" and "4" and melodic accents anywhere BUT on "1."
The first popular musical trend in the United States produced by this