A favorite of Benjamin Britten, he won acclaim in roles like Don Giovanni, Eugene Onegin and Falstaff until his affliction forced him to largely give up singing.
American Music was a marginal subfield in the 1960s when he began his research as a student, and then as a faculty member, at the University of Michigan.
Likened to a “court composer” for Germany, he wrote more than 500 pieces and was considered one of the most original and independent musical voices in Europe.