In the summer of 1968 he made his debut at Bayerische Staatsoper in Tristan und Isolde .
The conductor , Joseph Keilberth , died conducting the second act and the performance was cancelled .
In the summer of 1968 he made his debut at Bayerische Staatsoper in Tristan und Isolde , but the conductor , Joseph Keilberth , died conducting the second act and the performance was cancelled .