Blues has evolved from the unaccompanied vocal music and oral traditions of slaves imported from West Africa and rural blacks into a wide variety of styles and subgenres, with regional variations across the United States. Though blues, as it is now known, can be seen as a musical style based on both European harmonic structure and the African call-and-response tradition, transformed into an interplay of voice and trumpet. The origins of the blues are closely related to the religious music of the Afro-American community, the spirituals. The origins of spirituals go back much further than the blues, usually dating back to the middle of the 18th century, when the slaves were Christianized and began to sing and play Christian hymns, in particular those of Isaac Watts, which were very popular. Handy was a formally trained musician, composer and arranger who helped to popularize the blues by transcribing and orchestrating blues in an almost symphonic style, with bands and singers.
