L'ascension is a piece for orchestra

Orchestra

An orchestra is a sizable instrumental ensemble that contains sections of string, brass, woodwind, and percussion instruments. The term orchestra derives from the Greek ορχήστρα, the name for the area in front of an ancient Greek stage reserved for the Greek chorus...

, composed by Olivier Messiaen

Olivier Messiaen

Olivier Messiaen was a French composer, organist and ornithologist, one of the major composers of the 20th century. His music is rhythmically complex ; harmonically and melodically it is based on modes of limited transposition, which he abstracted from his early compositions and improvisations...

 in 1932-33. Messiaen described it as "4 meditations for orchestra".

The orchestral piece is in four brief sections:

1. Majesté du Christ demandant sa gloire à son Père ("The majesty of Christ demanding its glory of the Father")
2. Alleluias sereins d’une âme qui désire le ciel ("Serene alleluias of a soul that longs for heaven")
3. Alleluia sur la trompette, alleluia sur la cymbale ("Alleluia on the trumpet, alleluia on the cymbal")
4. Prière du Christ montant vers son Père ("Prayer of Christ ascending towards his Father")

A complete performance takes around 27 minutes.

Organ version

In 1933-34, Messiaen made a version for solo organ

Organ (music)

The organ , is a keyboard instrument of one or more divisions, each played with its own keyboard operated either with the hands or with the feet. The organ is a relatively old musical instrument in the Western musical tradition, dating from the time of Ctesibius of Alexandria who is credited with...

. The first, second and fourth movements are arrangements of the orchestral pieces, but Messiaen composed a new third movement, Transports de joie d'une âme devant la gloire du Christ qui est la sienne ("Ecstasies of a soul before the glory of Christ, which is its own glory"), usually just known as Transports de joie. .