Run time: Approx. 27 minutes

Early in my research on Mozart’s Symphony No. 40, I stumbled upon two quotes that brought my exploration of this beloved work to a standstill. I found myself unable to think past these two diametrically opposed views. The first, from music critic Charles Rosen, aligns with the way I have always interpreted this symphony, calling it, “a work of passion, violence, and grief.” The second, the one that stopped me in my tracks, was from 19th-century composer Robert Schumann, who found the work to be full of “weightless, Hellenic grace.” I was rather puzzled—were we listening to the same piece?

I must admit, I became a bit obsessed. I couldn’t stop thinking about Schumann’s words. Hellenic? Where exactly was he getting classical Greek art from this very German symphony? And weightless? We were, after all, talking about a composer at one of the lowest points in his life.

1788 found Mozart in a difficult position. His public concerts were growing increasingly rare and demand for his music was waning. On top of that, he was in serious gambling debt. He needed money badly, so in the summer of 1788 he produced an astonishing amount of work. His final three symphonies, 39, 40, and 41, were written in quick succession between June and August of that year, likely for a series that would bring him only a small amount of income.

The symphony’s key provides another tick for Rosen’s column. Mozart often turned to G-minor for his most grief-stricken moments, like in The Magic Flute when a brokenhearted Pamina tries to speak to Tamino, whom she does not know has taken a vow of silence, or in Mitridate, re di Ponto, when Aspisia mournfully laments “my heart palpates and greaves within my chest.” Mozart’s only other minor-key symphony, No. 25 from 1773 is also in G-minor, as is his fourth string quintet about which Tchaikovsky later said, ”No one has ever known as well how to interpret so exquisitely in music the sense of resigned and inconsolable sorrow.”

I listened to the piece more times than I can count, searching for its feathers, and still I felt I was looking at the late-period Mozart I knew—the Mozart of Don Giovanni or the Requiem, whose emotional breadth at times borders on ferocity. But I did find a stoic restraint in the pathos of this symphony that did not burden those other works. That constraint is the symphonic form.

Mozart was, at heart, a true child of the Classical era, which means he was, by definition, firmly invested in formal perfection. The symphonic form governed everything from the number of movements and their tempos to the harmonic paths available from a given starting key—constraints, yes, but also a puzzle to be solved. As my father, music theorist Gordon Sly, put it when I called him amid my Schumann-induced distress, “Mozart’s concerns about form are different in absolute music (music without narrative) versus texted music. In opera, he has text, he has the story. In a symphony, coherence can only be created by things like proportion, symmetry, and self-reference. Repetition is an absolute requirement for coherence.”

Suddenly, I understood. Proportion, symmetry—the hallmarks of Greco-Roman art. This, I believe, was Schumann’s meaning: not what Mozart said, but how he said it. Symphony No. 40 is indeed exquisitely executed, not only in the way it adheres to traditional symphonic form, but in the elegance of its transitions, the way it transforms the opening three-note motif into the thematic material for the entire first movement, and the way it balances tension with moments of repose.

The more I reflect on the classicism of this work—Hellenic or otherwise—the more I find that listening to it feels akin to looking at a great Greek sculpture. These works are full of power, but their might stems from their formal perfection: the grace of their lines, the proportion and symmetry of their features. Schumann also said, “The Greeks gave to ‘The Thunderer’ a radiant expression, and radiantly does Mozart launch his lightnings.”