Bluegrass music is a genre of American roots music that developed in the 1940s in the Appalachian region of the United States. The genre derives its name from the band Bill Monroe and the Blue Grass Boys. Like mainstream country music, it largely developed out of old-time music. Unlike country, it is traditionally played exclusively on acoustic instruments from Africa and Europe. Bluegrass has roots in traditional North European music, such as Irish ballads and dance tunes, as well as African American genres like blues and jazz.