Delta blues music is arguably one of the earliest types of "blues" music and is believed to have originated in the Mississippi Delta. Typical instruments used to play the Delta Blues are the acoustic guitar and the harmonica. Early recordings of this music emerged in the late 1920s and, during the depression; the harmonica dominated this sphere of music. The harmonica remains the most portable instrument used in traditional American folk and blues music. Although the earliest harmonicas date to Germany in the mid 19th century, this seemingly simple music instrument has become an icon in American music.