There is about an hour of music in the full Rosamunde score by Franz Schubert, but most of it (aside from the Overture) is rarely heard. Ironically, however, the third of the Entracte which Schubert composed for Rosamunde may be among his best-known music.
The serene first theme became the subject for piano variations in the second set of Impromptus, Op. 142 (D. 935), which were published in 1838, ten years after Schubert’s death.
The same theme also appears in the slow movement of the String Quartet in A minor, D. 804.
Here is the music, which is always lovely: