Hymns and hymnals have always been an essential and popular part of religious services and the Sunday-School movement recognized that music was as important a medium for appealing to children as literature. It was commonly believed, as the proverb has it, that "the devil has all the popular songs." The American Sunday-School Union, like the Christian Rock of today, "sought to displace the rollicking and ribald songs by cleaner and purer lyrics set to attractive music." That is to say, music calculated to appeal to young people. Isaac Watts' Songs for Children was one of the few texts that was in continued use in the nineteenth century but popular music tended to be of a coarser nature. Edwin Rice went so far as to suggest that children may even be agents of musical corruption; the "songs of the ale-house and of the brothel were too common on the streets and often crept into Christian homes through the children." This was related to a trend toward the regulation and formalization of singing-schools (informal singing groups), part of what came to be known as the "Better Music Movement," associated with figures like Lowell Mason.
For their part, the evangelical services of the early parts of the nineteenth century did not seem to be offering much in a way that might appeal to children. John S. Hart, a prominent Sunday-School editor, recalled "the grim and ponderous tune to which we youngsters were solemnly exhorted to trail our voices, while a hymn of equally unattractive character dragged its slow length." As with the literature of the period, Sunday-schools sought to create forms that would appeal to children. They collected simpler, livelier songs of praise compared with the dirges of the past hundred years. They also created instruction manuals for the teaching of musical notation, teaching melody, harmony and rhythm, often with homemade metronomic devices.
There were other trends in American religious music at the time as well. The Sacred Harp is a collection of hymns using the shape-note system (a notational scheme that uses four symbols to complement the oral four-syllable solfege system.) Spreading from New England to the South and West, shape-note singing drew on different folk tunes than those used by the Sunday-School Book Union and represents part of the rural, often oral tradition in American song. The Temperance Songster is a good example of adapting popular tunes for the purposes of a reform movement.
— Stephen Rachman, Department of English, Michigan State University