“The encounter with Weill’s music, which I had never heard before because it was not allowed to be played in the Third Reich, was absolutely overwhelming for me because it opened up a tonal but completely new sound world,” Mr. Reimann said in a 2018 interview for his former secondary school’s annual publication.
He also began composing short works for piano at 10. Shortly after, he accompanied his mother’s vocal students at concerts.
In 1955, after graduating from high school, he worked at the newly founded opera studio of the Städtische Oper Berlin, now the Deutsche Oper, while taking composition and piano classes at the city’s music conservatory. He also briefly studied musicology at the University of Vienna.
One of his professors at the Berlin conservatory was the influential German composer Boris Blacher, who advised Mr. Reimann to avoid the avant-garde hubs of Darmstadt and Donaueschingen — incubators of modern music with reputations for being experimental but dogmatic — and instead to forge his own path. Doing so, he distinguished himself from older contemporaries, like Karlheinz Stockhausen and Hans Werner Henze, and throughout his long career he remained radically individual, even solitary, as an artist who never belonged to any musical movement or school.
Starting in his 20s, Mr. Reimann accompanied Mr. Fischer-Dieskau and the mezzo-soprano Brigitte Fassbaender in recitals and wrote music for them. Throughout his career he remained a sought-after and frequently recorded accompanist, and he championed young composers through the establishment of the Busoni Composition Prize in 1988 and the Aribert Reimann Foundation, which was founded in 2006.
In 1962, his concert piece, “Fünf Gedichte von Paul Celan,” or “Five Poems by Paul Celan,” premiered at the Berliner Festwochen, an annual performing arts festival, with Mr. Fischer-Dieskau as soloist. Mr. Reimann had met Mr. Celan, a Jewish-Romanian poet who had survived the Holocaust, in Paris in 1957, and was among the first to set his haunting German-language poems to music. Mr. Reimann returned to Mr. Celan’s poetry in 1971, a year after the writer died by suicide, for “Zyklus,” a setting of six poems in a single movement of about 20 minutes.