Adagio in B minor, K. 540

Mozart entered the Adagio in B minor in his own thematic catalogue on 19 March 1788, giving no indication of why he wrote it or for whom. It is his only completed keyboard piece in that key, and it stands apart from the sonatas of the same period: a slow movement with no work to belong to, unusually chromatic, its phrases broken off again and again by silence. The closing bars turn to B major. Because no commission and no dedicatee is recorded, the piece has attracted biographical readings that the surviving documents do not support.