Composed: 1786
Length: c. 30 minutes
Orchestration: flute, 2 oboes, 2 bassoons, 2 horns, 2 trumpets, timpani, strings, and solo piano
First Los Angeles Philharmonic performance: November 16, 1961, with soloist Leon Fleisher, Walter Hendl conducting

Explaining the reasons for the decline in Mozart’s fortunes during the later 1780s, musicologist Joseph Kerman points to the C-minor Concerto, K. 491, the work that preceded K. 503 in the composer’s keyboard concerto canon. “With his C-minor Concerto,” Kerman writes of Mozart, “he had put his tacit contract with [the Viennese audience] at risk; if any of his concert subscribers felt affronted and alienated by this deeply subversive work, we could hardly blame them.”

If the C-minor Concerto is about conflict, even rebellion, the C-major Concerto, K. 503 – the date of its first performance remains conjectural – is its resolution: its self-confidence announced by a series of majestic chords built on the C-major triad, the pulse quickening as the energy builds. Shortly, however, the private Mozart asserts himself in the quiet exchange of oboe and bassoon, before momentum and volume gather again for the proclamatory entry of the piano. But the Mozart of 1786 never gives us the expected. Instead, the solo, introduced by a little violin trill, steps forward timidly, picking up bits of the preceding string theme, as it begins its rise to eminence. Still, the piano never loses sight of its role as the orchestra’s partner, meshing with the ensemble in the kinds of conversations that Mozart invented and at which no one has ever surpassed him.

The Andante is a sonata movement with a barely noticeable development: a few measures of transition. It is, then, in two halves, the material of the second varying that of the first slightly, yet tellingly. The movement is made up chiefly of two-bar phrases, but there is never a feeling of form governing content, or of head governing heart, so natural-sounding is the music’s liquid flow.

The Finale is grand in all aspects but length. It also contains an episode that no matter how frequently encountered remains astonishing: midway through, the piano aggressively states a theme in A minor, followed by three peremptory chords from the full orchestra, affording a rude transition to the major, whereupon the piano sings a little tune of utmost poignancy, the bass line provided not, as is customary, by the pianist’s left hand but by the double-basses, first alone, then softened by the addition of bassoon, before being taken over by the cellos, with the piano’s tune briefly usurped by the flute and oboe. Listen for it.

— Herbert Glass