fallen into obscurity

Music Bach's Cello Suites had fallen into obscurity until a teenager stumbled upon an early printing in a second hand shop:

"For those musicians who knew of them, the Cello Suites were considered dry, technical exercises, of some pedagogical value, but not fit for the concert hall. When Casals started figuring out the music he didn't have a model. He had to reinvent the music, because the autograph manuscript had gone missing and the few copies that survived differ in details. We still don't know what Bach had in mind for tempo, dynamics, bowing or styles of play. The sheet music, as a result, comes with poetic licence attached."

The recordings that Casals finally made of the suites in the mid-30s (mentioned in the article) are available on Spotify.