French composer Olivier Messiaen created his best known work while being a prisoner of war in the German Stalag VIIIa. He started it while on his way there, and finished with the help of a friendly guard giving him a pencil. While Messiaen later exaggerated that the first performance in the camp was in front of 5000 inmates and with decrepit instruments, the whole situation gives the piece meaning.
The first parts Messiaen wrote were for a trio of clarinet, violin and cello. He later added himself at the piano to the mix. As the title in French says, this is music for the end of times. It is dedicated to the angel that announces it.
And I saw another mighty angel come down from heaven, clothed with a cloud: and a rainbow was upon his head, and his face was as it were the sun, and his feet as pillars of fire ... and he set his right foot upon the sea, and his left foot on the earth .... And the angel which I saw stand upon the sea and upon the earth lifted up his hand to heaven, and sware by him that liveth for ever and ever ... that there should be time no longer: But in the days of the voice of the seventh angel, when he shall begin to sound, the mystery of God should be finished (Book of Revelation Rev 10:1-2, 5-7 King James Version).