While in Prague I caught the tail end of a TV show about Antonín Dvořák's time in America. Dvořák was fascinated with American folk music (Negro spirituals, etc.) and worked tirelessly to encourage his students to develop from such sources a native art music. His students are virtually unknown today, but the students of his students include Duke Ellington, James P. Johnson, George Gershwin, and Aaron Copland. You can find a bit of the story here. A topic for further reading, I think.