Even before the advent of phonograph and radio, the principal means of transmission for musical traditions was through the family. Family groups, such as the Carter Family, the Stonemans, and Bela Lam and His Greene County Singers, played a variety of music: songs and ballads learned from parents and grandparents, old dance tunes, nineteenth century parlor ballads that had passed into folk tradition, traditional religious music, and popular blues and jazz tunes learned from records or the radio. The family band persisted as an important musical unit until the end of World War II.