Mozart often began work on a composition only to put it aside, unfinished. Some of these fragments contain wonderful music, as is proved by these three piano trio fragments. Mozart composed them at different times as individualmovements, though the posthumous first edition brought them together as a supposedly new and unknown piano trio by the composer, and on this basis they were given the number 442 in Köchel's catalogue. The first edition usedcompletions by Mozart's friend Abbé Maximilian Sta