I played a piece called wiegenleid (lullaby) for my ABRSM cello grade 3 about 18 years ago. (told you it was a challenge!!) and I would love the sheet music again. I don't know the composer but I had an idea it was Bach, although I might be wrong. I know his is a complete shot in the dark but I have been unable to find it and someone maybe did the same piece and remembers the details. I would know it immediately and my daughter actually has a music box that plays it.

Believe it or not I found the piece. It was actually by Schubert. and i found it in a music shop in the city