Question: For which opera was the teacher of Der Bärenhäuter best known?
Sentence (from "Nun komm, der Heiden Heiland"): It was used widely in organ settings by Protestant baroque composers, most notably Johann Sebastian Bach: he set it as the opening chorale prelude BWV 599 of Orgelbüchlein; and three times—as BWV 659 (one of his best known organ compositions), BWV 660 and BWV 661—in his Great Eighteen Chorale Preludes.
Relevant evidence: No