The ancestors of today's African American population were brought to the United States as slaves, working primarily in the plantations of the South. They were from hundreds of tribes across West Africa, and they brought with them certain traits of West African music including call and response vocals and complexly rhythmic music, as well as syncopated beats and shifting accents. The African musical focus on rhythmic singing and dancing was brought to the New World, and where it became part of a distinct folk culture that helped Africans "retain continuity with their past through music". The first slaves in the United States sang work songs, field hollersand, following Christianization, hymns. In the 19th century, a Great Awakening of religious fervor gripped people across the country, especially in the South. Protestant hymns written mostly by New England preachers became a feature of camp meetings held among devout Christians across the South. When blacks began singing adapted versions of these hymns, they were called Negro spirituals. It was from these roots, of spiritual songs, work songs and field hollers, that blues, jazz and gospel developed.