We’re using Quatuor pour la fin du temps (Quartet for the End of Time) 1940 – 41, by Olivier Messiaen (1908 – 1992), as the basis for several concepts introduced in chapter 6 (Rhythm and Meter). This post will focus on the first movement, “Liturgie de Cristal,” as an example of isorhythm.
You may have studied isorhythm in the context of 14th- and 15th-century music – notably, isorhythmic motets. You can also find isorhythmic procedures in other 20th- and 21st-century composers, and in the music of India. An isorhythm features a repeating rhythmic pattern and an independent repeating pitch pattern. Messiaen referred to the repeating rhythmic pattern as a rhythmic pedal.
The cello and piano both feature independent isorhythms. The cello has the shortest repeating pitch pattern (5 pitches), along with a 15-duration rhythmic pattern. The pitch pattern in the cello is C4, E-natural4, D4, F#4, Bb3. The rhythmic pattern is substantially longer at 15 note values, but having the rhythmic pattern be a whole-number multiple of the pitch pattern means that the rhythmic pattern will always start with the beginning of the pitch pattern. The rhythmic pattern lasting for a total duration of 16.5 beats, the pattern will alternate starting off the beat, and on the beat.
The piano isorhythm is less synchronized than the one in the cello, and it has a longer pitch pattern than rhythmic pattern. The rhythmic pattern is 17 note values in length, starting with the three quarter notes in succession, and the duration of the entire pattern is 13 beats. The pattern always starts on the beat but in different part of the measure each time. The pitch pattern is comprised of 29 chords. The number of chords in the pitch pattern and the number of rhythmic values in its pattern are both prime numbers. These two patterns will not start together for 17 x 29 repetitions (493), which is much longer than the duration of the movement. This lack of synchronization, along with the lack of synchronization between the two isorhythms, contributes to a static feeling for the movement, and a feeling of incompleteness.
To sum up the two isorhythms:
- cello: 5 pitches, 15 rhythmic values, total duration of 16.5 beats.
- piano: 29 chords, 17 rhythmic values, total duration of 13 beats.
The violin and the clarinet both have the performance indication of “comme un oiseau” (like a bird). These two instruments are providing music that resembles bird calls. Along with Messiaen’s devout Catholicism, he was greatly influenced by the music of birds, going as far as transcribing their calls and incorporating them into his works.