Ferdinand Joseph LaMothe (later Morton; c. September 20, 1890 – July 10, 1941), known professionally as Jelly Roll Morton, was an American ragtime and jazz pianist, bandleader, and composer. Morton was jazz's first arranger, proving that a genre rooted in improvisation could retain its essential characteristics when notated. His composition "Jelly Roll Blues", published in 1915, was one of the first published jazz compositions. He also claimed to have invented the genre.