If we take jazz to mean a free-form improvisation on a theme, then Rhapsody in Blue by George Gershwin (Great American Things, February 24, 2010) should be classified as a classical work. And it is definitely in the symphonic tradition. Yet this piece stretched the normal perception, and blended jazz rhythms and progressions to create a kind of music that surprised and excited Americans when it debuted in 1924, promoted as a “jazz concerto.”
From its opening clarinet glissando through many changing sections, Rhapsody in Blue is totally American in its feel and motifs. (Perhaps that’s why United Airlines used parts of it in its advertising some years ago.) The website Classical.Net says this about Gershwin’s masterpiece:
With his first major piece, Gershwin invented a unique symphonic idiom, to this day still argued over. Gershwin, of course, was not the first to blend jazz and classical music. One could make cases for Debussy, Scott Joplin, or Milhaud as important pioneers and, even better, as creators of masterworks which used jazz. All of them, however, had exploited jazz’s “chamber” qualities. From the Rhapsody’s opening clarinet wail, Gershwin created not symphonic jazz, but the Gershwin idiom: an outdoor, urban, big-hearted, super-Romantic, and thoroughly assured poetry.
Hear it all here, performed by the New York Philharmonic: