The prelude is one of Bach’s most well-loved pieces and often appears as background music in an advertisement. The French composer Gounod improvised a melody over the piece in 1843 which became an Ave Maria, sung at many a wedding or funeral. The pattern of broken chords in changing harmonies is so simple that it can be played effectively by a relative beginner at the piano. The fugue is for 4 voices, starting with the alto voice.