The Key to Beethoven's Piano Sonatas

Compositions in Ludwig van Beethoven’s time had to be in one of 24 keys: major or minor for each of the 12 notes in the chromatic scale (C, C-sharp, D, etc.). Some of those keys are more convenient than others for certain instruments because of how those instruments are tuned. The common clarinet, for instance, is tuned in B-flat, and is more awkward to play in distant keys (keys that share few or no notes with B-flat major). The piano, however, is open to all keys. How, then, does a composer decide which key to use? Of course, it may be that there is no choice to be made: that the composer simply accepts the key in which the first idea presents itself.

This seems to have been the way Beethoven worked. His sketchbooks have largely survived, and allow scholars to trace his working practices. A theme might be altered before being incorporated into a composition, but its key did not change. A striking case is the opening idea of the “Hammerklavier” Sonata (Op. 106, 1817–18), which Beethoven first sketched for a cantata to honor his patron and friend the Archduke Rudolph. In that work, the same assertive chords that open the sonata were to set the words “Vivat, vivat Rudolphus!” (“Long live Rudolph!”). Transferred to a piano sonata dedicated to the archduke, the idea lost its words but kept its key of B-flat major: the key was imprinted in the idea as firmly as its rhythm. But why B-flat major? And why did Beethoven’s other piano sonatas come to be in the keys they are in?

If this were a completely random matter, we would expect each of the 24 keys to be represented among the 32 sonatas once or twice. That is not, however, what we see. For one thing, minor keys are conspicuously underrepresented: there are only eight minor-key sonatas—not a full half of the total but precisely a quarter.

Here, we have to consider the market. Piano sonatas were composed not for public recitals (which did not yet exist), but for publication, and then for sale to home pianists, of whom there were many among the bourgeoisie of Europe and, increasingly, the US. (Industrial-scale production of pianos in North America was started by Jonas Chickering in Boston in 1823, right after Beethoven composed his last sonata.)

Publishers likely avoided pieces that, to an amateur, would look difficult, as minor-key music often did. (It also had an emotional charge that might put off home pianists wanting to entertain their family and friends.) For the same reason, a complicated key signature would be a no-no. Only once did Beethoven write a sonata requiring a signature of more than four sharps or flats: Op. 78 in F-sharp major (“à Thérèse”), in which both movements have six sharps.

Hidden in an internal movement, however, inspecting purchasers would sometimes find a key signature that would be bound to make them work hard: the five flats of D-flat major, for instance, in the middle movement of the “Moonlight” Sonata (Op. 27 No. 2, 1802)—and that key signature is only one feature of this movement that made amateur brows wrinkle after the relatively straightforward opening “Adagio sostenuto” that got the sonata its name. But D-flat major is, in fact, Beethoven’s concession to the player—an easier equivalent to C-sharp major, with its seven sharps. What we hear, then, is what we find quite often in Beethoven: the music refreshing itself, straightening up, changing the key from minor to major but keeping the keynote.

Of course, Beethoven would not be Beethoven if he had always bowed to the convenience of amateur performers—and his publishers, who knew what they had in him, did not expect him to. He could make up his own mind about keys. So what other considerations might have influenced him?

One was how certain keys would arouse particular associations of feeling and atmosphere. This was an old notion, formulated by the music theorist Johann Mattheson (1681–1764), a contemporary of J.S. Bach and G.F. Handel. Beethoven read Mattheson, but his sense of the meanings of keys was informed much more by his immediate predecessors, especially Wolfgang Amadeus Mozart. D minor, for instance was a powerful, dramatic key for Mozart, the home key of his opera Don Giovanni. That was how Beethoven understood it, too, not least in his single piano sonata in D minor, Op. 31 No. 2 (1801–02), known as the “Tempest.”

Like the “Moonlight,” the “Tempest” Sonata did not gain its name until after Beethoven’s death; the only sonatas named during his lifetime were the Pathétique (Op. 13, 1798)—or “Grande sonate pathétique,” as it was called by its first publisher (Beethoven approved)—and “Les Adieux” (“The Farewell”; Op. 81a, 1809–10), in which the idea was Beethoven’s own. These monikers give us firsthand information about Beethoven’s understanding of key as an expressively meaningful entity. The Pathétique (the word means “pathos-driven” rather than “pathetic”) was the second of his two sonatas in C minor, which was always a stormy key for him, as in the Fifth Symphony, a work foreshadowed by his other C-minor sonata, the “Little Pathétique” (Op. 10 No. 1, 1795–97). The “Les Adieux” Sonata also features the key of C minor in its slow movement, the outer movements being in E-flat major. This work has a whole programme in words Beethoven inscribed over the movements: “The Farewell,” “The Absence” (the C-minor movement), and “The Return.”

Beethoven: Sonata in E-flat major for Piano, Op. 81a, "Les adieux"

“Les Adieux” is one of four piano sonatas in E-flat major, which, again, has clear connotations in Beethoven’s music: grandeur and fullness, as in the Eroica Symphony (No. 3) and “Emperor” Piano Concerto (No. 5). All the other sonatas in E-flat major similarly seem to take solidity as an opportunity to be experimental—or more experimental than was usual for Beethoven. The earliest one is a work in four movements, playing altogether for almost half an hour and, probably for that reason, published alone as Op. 7 (the “Grand Sonata,” 1796–97). Both of the next E-flat-major sonatas are also in four movements, but with special features: in Op. 27 No. 1 (“quasi una fantasia” [“like a fantasy”], 1800–01), the movements are to be played attacca (without a break); Op. 31 No. 3 (“The Hunt,” 1801–02) has no slow movements.

Other keys with an evident association in Beethoven’s piano sonatas include C major—for its bold straightforwardness, as in the “Waldstein” Sonata (Op. 53, 1803–04)—and A-flat major—for the luminosity and songfulness it brings to Op. 26 (1800–01) and Beethoven’s penultimate sonata, Op. 110 (1821); both of the A-flat-major works have relaxed opening movements to show off the qualities of the home key, but also melancholy music in the unusual key of A-flat minor. (Pianists still must live with its seven flats.)

Something else that influenced Beethoven in the matter of key choice was—to go back to the beginning—a question of tuning. Various tuning systems were in use at the time, and they probably did not include the equal-temperament system that is ubiquitous today. In equal temperament, all intervals between notes are exactly the same size. But with the tuning systems of that time, Beethoven would have expected marginal, but telling, differences which would have made those moves to A-flat minor, for example, all the more extreme.

Differences between keys would have shown up more on the lighter, wood-framed pianos of Beethoven’s day—which raises the question of why we still hear these differences today, on our much heavier, cast-iron-framed instruments tuned in equal temperament. That can only be because he wrote the music to sound that way: that the key was integral to the way a work sounded. This would explain why it went unchanged from the very beginning of the compositional process. Finding the key was right there at the start—then you did something with it. And, if you were Beethoven, you unlocked a whole sonata.

________

Article by Paul Griffiths