G minor has been considered the key through which Wolfgang Amadeus Mozart best expressed sadness and tragedy, and many of his minor key works are in G minor. Though Mozart touched on various minor keys in his symphonies, G minor is the only minor key he used as a main key for his numbered symphonies. Isolated sections in this key within Mozart's compositions may also evoke an atmosphere of grand tragedy, one example being the stormy G minor middle section to the otherwise serene B♭ major slow movement in the Piano Concerto No. 20.