The Piano Quartet in G minor, K.478, bears the date 16th October 1785 and was completed on that date in Vienna. By the 20th November Mozart was writing to Hoffmeister with some urgency, seeking money. By the 2nd of December Leopold Mozart, in a letter to his daughter, gives news of the receipt of the work, together with copies of the quartets Mozart had recently dedicated to Haydn.
The key of G minor is a dramatic one and the Piano Quartet starts with a united opening figure, to which the piano offers a reply. The re-appearance of the opening figure elicits a further version of it from the piano, returning in what immediately follows. The piano introduces the B flat major second subject, to which the string instruments have something to add, the substance of this is taken up by the piano. There is a central development, with versions of the opening figure.
The entire quartet represents a wonderful conversation Between the instruments, with both sad and joyful content.
Here is a performance of the Mozart Piano Quartet KV 478:
