 Uniting these eras is the persistence and development of orchestral jazz, accomplished in large part by the immense career of Duke Ellington.The most marked shifts from New Orleans and Chicago styles of jazz to orchestral jazz included the shift from polyphony to homophony, the general expansion of instrumentation, and a greater emphasis on pre-arranged compositions rather than collective improvisation.Prior to 1930, big bands were composed of trumpets, trombones, saxophones or clarinets, and a rhythm section made up of tuba, banjo, piano, and drums.