Gospel music is a genre of Christian music. The creation, performance, significance, and even the definition of gospel music varies according to culture and social context. Gospel music is composed and performed for many purposes, including aesthetic pleasure, religious or ceremonial purposes, and as an entertainment product for the marketplace. Gospel music usually has dominant vocals (often with strong use of harmony) with Christian lyrics. Gospel music can be traced to the early 17th century, with roots in the black oral tradition. Hymns and sacred songs were often repeated in a call and response fashion. Most of the churches relied on hand clapping and foot stomping as rhythmic accompaniment. Most of the singing was done a cappella. The first published use of the term "gospel song" probably appeared in 1874. The original gospel songs were written and composed by authors such as George F. Root, Philip Bliss, Charles H. Gabriel, William Howard Doane, and Fanny Crosby. Gospel music publishing houses emerged. The advent of radio in the 1920s greatly increased the audience for gospel music. Following World War II, gospel music moved into major auditoriums, and gospel music concerts became quite elaborate.