Piano Quartet No. 1 in G minor, KV 478

Composed in Vienna in 1785, this is the founding work of the piano quartet — there was essentially no repertoire for the combination before it. Mozart had contracted with the publisher Hoffmeister for three such pieces, but sales were poor and Hoffmeister released him on the grounds that the music was too difficult. G minor in Mozart is always a key of unrest, and the stark unison motif that opens the first movement runs through the whole work.