Boléro is a one-movement orchestral piece by the French composer Maurice Ravel (1875–1937). Originally composed as a ballet commissioned by Russian actress and dancer Ida Rubinstein, the piece, which premiered in 1928, is Ravel's most famous musical composition.
Boléro is "Ravel's most straightforward composition in any medium". The music is in C major, 3/4 time, beginning pianissimo and rising in a continuous crescendo to fortissimo possibile (as loud as possible). It is built over an unchanging ostinato rhythm played on one or more snare drums that remains constant throughout the piece.
On top of this rhythm two melodies are heard, each of 18 bars' duration, and each played twice alternately. The first melody is diatonic, the second melody introduces more jazz-influenced elements, with syncopation and flattened notes (technically it is in the Phrygian mode). The first melody descends through one octave, the second melody descends through two octaves. The bass line and accompaniment are initially played on pizzicato strings, mainly using rudimentary tonic and dominant notes. Tension is provided by the contrast between the steady percussive rhythm, and the "expressive vocal melody trying to break free".
Interest is maintained by constant reorchestration of the theme, leading to a variety of timbres, and by a steady crescendo. Both themes are repeated a total of eight times. At the climax, the first theme is repeated a ninth time, then the second theme takes over and breaks briefly into a new tune in E major before finally returning to the tonic key of C major.
The melody is passed among different instruments: 1) flute, 2) clarinet, 3) bassoon, 4) E-flat clarinet, 5) oboe d'amore, 6) trumpet, and flute (latter is not heard clearly and in higher octave than the first part), 7) tenor saxophone, 8) soprano saxophone, 9) horn, piccolos and celesta; 10) oboe, English horn and clarinet; 11) trombone, 12) some of the wind instruments, 13) first violins and some wind instruments, 14) first and second violins together with some wind instruments, 15) violins and some of the wind instruments, 16) some instruments in the orchestra, 17) and finally most but not all the instruments in the orchestra (with bass drum, cymbals and tam-tam). While the melody continues to be played in C throughout, from the middle onwards other instruments double it in different keys. The first such doubling involves a horn playing the melody in C, while a celeste doubles it 2 and 3 octaves above and two piccolos play the melody in the keys of G and E, respectively. This functions as a reinforcement of the 1st, 2nd, 3rd and 4th overtones of each note of the melody. The other significant "key doubling" involves sounding the melody a 5th above or a 4th below, in G major. Other than these "key doublings", Ravel simply harmonizes the melody using diatonic chords.
The accompaniment becomes gradually thicker and louder until the whole orchestra is playing at the very end. Just before the end (rehearsal number 18 in the score), there is a sudden change of key to E major, though C major is reestablished after just eight bars. Six bars from the end, the bass drum, cymbals and tam-tam make their first entry, and the trombones play raucous glissandi while the whole orchestra beats out the rhythm that has been played on the snare drum from the very first bar. Finally, the work descends from a dissonant D-flat chord to a C major chord.
