The art of music, Vol. 05 (of 14… (1915)
“ The ballad opera was strictly not opera at all, but only a lively and merry farce (often suggesting the operetta librettos of Sir William Gilbert) interspersed with songs and duets. These songs were at first but popular melodies of the street or countryside, adapted to new words, assuring the popularity of the opera because the tunes were favorites. As the number of native tunes seemed insufficient to supply the enormous number of ballad operas, the writers engaged well-known musicians to write original tunes in the same manner—sometimes as many as eight or ten composers for one work. ”
