World War I Sheet Music OnlineFrom 1914 through 1920 the Library of Congress acquired over 14,000 pieces of sheet music relating to what ultimately became known as the First World War, with the greatest number coming from the years of the United States' active involvement (1917-1918) and the immediate postwar period. America's entry into the war came at a time when popular songwriting and the music publishing industry, centered in New York's Tin Pan Alley, was at its height and a new musical form known as "jazz" was emerging. The sheet music collection represents the intersection of this rich output of popular song and the consciousness of a nation at war that was itself emerging, as a major world power.