IIRC both Mozart and Schubert have fallen in and out of the repertoire and had to be "rediscovered" by musicologists in the 20th century as people didn't "get"

IIRC both Mozart and Schubert have fallen in and out of the repertoire and had to be "rediscovered" by musicologists in the 20th century as people didn't "get" their music - at one point people thought Mozart was only good for writing light music. (no source to hand...)