Just as Victor Herbert had progressed within his genre and beyond his operetta roots, so did Jerome Kern. Kern left the safe enclave of the Princess Theatre and started writing a series of shows, ending with the impressive show, Sunny (1925.33). Impressive as Sunny might have been, Kern was also aware of and listening to the music coming from George Gershwin, Richard Rodgers and Vincent Youmans.
What Sunny did was to prepare Kern to write the score for Show Boat (1927.67). His score for Show Boat prepared him to write more complex compositions for single voice and multiple voices in Sweet Adeline (1929.31) and Very Warm for May (1939.28). Elsewhere on the website, we compared the five voice harmonies of “Some Girl Is on Your Mind” from Sweet Adeline with the quartet from Rigoletto and the quintet from West Side Story. The point here is that each composer must make this leap forward, must work out the harmonic structure and counterpoint to his or her own satisfaction.
We can see this same progression with Gershwin, as he mastered the complexity of writing multi-voice music in the duet between Porgy and Bess (“Bess, You Is My Woman Now”) in Porgy and Bess (1935.13)
Just as Herbert’s great score in 1917 was overshadowed by Kern’s new compositions, Kern’s great success with Show Boat would give way to the next era of compositions written by Gershwin and Rodgers.