Luigi Nono was influenced by Schoenberg and the atonal composers. He was influenced philosophically by Marxism. He has written opera of note in the late twentieth century. Prometeo is an opera described by him as a "Tragedia dell'Ascolto' (Tragedy for Listening). It was premiered at the church of San Lorenzo, Venezia on 25th September 1984 under Claudio Abbado. In the late nineties, he gave another great performance of this opera with the Berlin Philharmonic.
There is a remarkable three-part vocal fragment running as a thread through the opera. Nono enhances the natural clarity of the human voice by letting it sing on the sonorous intervals of octaves and the fourths. The tones are sustained for a long time so that it seems as if the voice only sings vowels.