For many years, he had faded into obscurity. It is known that in his later years, due to deep depression, Tannhauser destroyed as much of his work as he could. As a key figure in the avant-garde music scene of the 20th century, he made substantial contributions to technological experimentation in music, creating a multitude of compositions, including three avant-garde operas for chamber orchestra and the Ondes Martenot.
On July 10, 2014, researchers unexpectedly discovered manuscripts related to the artist that were feared lost forever. These documents, now in Italy, include an unpublished biography and various scores. The material will be evaluated for potential dissemination.
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