"Do-Re-Mi" is a show tune from the 1959 Rodgers and Hammerstein musical "The Sound of Music". Within the story, it is used by Maria to teach the solfège of the major musical scale to the Von Trapp children who learn to sing for the first time, even though their father disallowed frivolity after their mother's death. Each syllable of the musical solfège system appears in the song's lyrics, sung on the pitch it names. Rodgers was helped in its creation by long-time arranger Trude Rittmann who devised the extended vocal sequence in the song. According to assistant conductor Peter Howard, the heart of the number – in which Maria assigns a musical tone to each child, like so many Swiss bell ringers – was devised in rehearsal by Rittmann (who was credited for choral arrangements) and choreographer Joe Layton. The fourteen note and tune lyric – 'when you know the notes to sing...' – were provided by Rodgers and Hammerstein; the rest, apparently, came from Rittmann. Howard: 'Rodgers allowed her to do whatever she liked. When we started doing the staging of it, Joe took over. He asked Trude for certain parts to be repeated, certain embellishments.'