It is not often that a classical music concert triggers a riot and ends with the theatre being invaded by riot police.
But that's what happened on the opening night of Henze's oratorio Das Floss der Medusa (The Raft of the Medusa) in Hamburg on 9 December 1968. The event, which he was at, confirmed Henze's dim view of his country and cemented his political radicalisation. His recent death at the age of 86 is a sad loss.
Hans Werner Henze was born in 1928. He was the son of a teacher who became a fan of Hitler and enrolled him in the Hitler Youth. But Hans loathed the Nazis. From an early age he showed musical talent and was more or less openly homosexual. He did not like his father or the fatherland.
In 1947 he attended the Darmstadt new music school which was then the centre of serial music - the avant-garde wing of classical music. He became one of the school's leading advocates at the age of 22. Their work was atonal and based on Schoenberg and the second Viennese school; it was everything that the Nazis hated. It was also difficult and cultish.
To the outrage of other avant-garde composers such as Stockhausen and Boulez, Henze moved away from serialism to an open expressionist style, borrowing from a whole range of music influences including Stravinsky, jazz and Arabic music.
From the mid-1960s this proved to be popular, but the rather puritan serialists saw this as a populist sell out. Some also disliked his increasingly radical politics and his view that music should promote revolution. Henze was a prolific composer as well as a great teacher and promoter of young composers.
He was mortified that the same officials who had run the Nazi state continued to run West Germany. What's more, West Germany kept the Nazis' anti-gay law until 1969. Henze left West Germany for Italy in 1953, citing homophobia and reactionary politics. He joined the Italian Communist Party and declared himself a Marxist. Henze lived most of his life in Italy with his partner Fausto Moroni.
Henze was part of a generation of classical composers, like Luigi Nono in Italy and Cornelius Cardew in Britain, who became radical in the 60s and wanted to produce music for the revolution. Henze worked briefly in the US, and was influenced by the civil rights and anti-war movements. From the late 60s to the late 70s he produced a series of inspired works with the general themes of denouncing capitalism and promoting revolution.
At the time of the riot in Hamburg in 1968, Henze closely identified with the student revolt. He sheltered the student leader Rudi Dutschke. Henze's composition appeared just after the death of Che Guevara and was dedicated to him. The performance was to be sung under a poster of Che, but the orchestra manager objected and tore it down; radical students from the audience reacted by raising a red flag on stage under which the German choir refused to sing. Then all hell and the riot police broke loose.
All of Henze's works from this period have clear political statements and aims. His 6th symphony (1969) includes songs of the Vietnamese Liberation Front; his 22-song cycle Voices (1973) concerns themes of alienation and oppression; El Cimarron (1970) is the story of a runaway slave; La Cubana includes poems by Brecht and Enzenberger; his cantata Essay on Pigs and his huge opera We come to the River (1976) is the story of a failed revolution with 111 roles and over 50 singers.
With the decline of the left in the 80s, it is no coincidence that classical music has largely returned to quietism, minimalism and mysticism. Henze's music comes from a time of revolution when even the concert hall became a place for rioting and fighting the police.