String Quartet No. 21 in D major (K. 575) — the first “Prussian” Quartet
par Wolfgang Amadeus Mozart
Mozart’s String Quartet No. 21 in D major (K. 575) was completed in Vienna in June 1789 and stands at the head of the three so‑called “Prussian” Quartets (K. 575, 589, 590). Written with the cello-loving King Friedrich Wilhelm II of Prussia in mind, it refashions the quartet texture into something notably more cantabile and concertante—without surrendering the genre’s hard-won equality of voices.
Background and Context
By the summer of 1789 Wolfgang Amadeus Mozart (1756–1791) was navigating a Viennese musical economy made uncertain by war and dwindling aristocratic spending, even as his ambitions as an instrumental composer remained undimmed. A key biographical hinge lies just a few weeks earlier: Mozart’s spring 1789 journey to northern Germany and Berlin, undertaken in search of employment and patrons, brought him into the orbit of the Prussian court and its music-loving monarch, King Friedrich Wilhelm II (1744–1797) [1]. The King’s reputation as an amateur cellist mattered: it created a market for chamber music in which the cello could be more than harmonic ground—an opportunity Mozart took up with unusual imagination.
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The nickname “Prussian” can mislead if taken to imply a neat courtly commission, promptly fulfilled. The documents suggest something more characteristic of Mozart’s late career: a composer writing at the intersection of aspiration, financial pressure, and aesthetic experiment. In June–July 1789 Mozart was already appealing to his friend and creditor Michael von Puchberg for emergency funds, and the Prussian project appears in this same period as both an artistic plan and a hoped-for income stream [2]. The quartet K. 575—fresh, open-air in tone, and strikingly generous to the cello—should therefore be heard not merely as “music for a patron,” but as a late-style recalibration of quartet rhetoric.
Notably, Mozart’s own catalogue entry for K. 575 is unusually explicit: he described it as a quartet “for His Majesty the King of Prussia” [3]. Modern scholarship often points out that, of the three “Prussian” quartets, this is the only one he labeled in precisely this way—an autobiographical detail that hints at how closely the composer associated this first essay with the royal connection [3].
Composition and Dedication
K. 575 was composed in Vienna and is generally dated to June 1789 [1]. Mozart’s Berlin contacts are a vital part of the backstory, but the work itself is a Viennese artifact: it belongs to the same late phase that produced the great string quintets and the clarinet music, where instrumental lines grow more vocal, phrase structures breathe more freely, and the “learned” and “singing” styles are fused without ostentation.
The dedication question is also part of the quartet’s fascination. The King of Prussia is routinely described as the dedicatee, and Mozart’s catalogue entry supports that association [3]. Yet surviving evidence for the commission’s exact terms is thin, and later biographical tradition embroidered the story with payments and gifts (a reminder that nineteenth-century Mozart biography mixes documentation with anecdote) [4]. What is secure is the musical consequence of writing “for a cellist king”: the cello is treated not as continuo-like reinforcement but as a melodic actor, often positioned in its high register where its timbre acquires a tenor-like sheen.
A further layer of context comes from editorial and source study. The Neue Mozart-Ausgabe commentary on the string quartets places K. 575 within a late aesthetic that increasingly explores blended textures and roles rather than the earlier polarity of “first violin versus accompaniment” [5]. This is not the heroic argumentative quartet world associated with Haydn’s most knotty works; it is, instead, a refined conversational art that still assumes connoisseurship, but seduces through tone, balance, and the calibration of instrumental colour.
Form and Musical Character
Across its four movements, K. 575 projects an outward brightness that is continually complicated by Mozart’s handling of register and voice-leading. The quartet is “Prussian” not because it is showy, but because it rethinks what counts as virtuosity in chamber music: not display, but the ability to sustain long-breathed cantabile lines while maintaining quartet equilibrium.
I. Allegretto (D major)
Mozart opens with a theme that seems almost disarmingly plain—an Allegretto rather than an emphatic Allegro—but its very restraint creates room for subtle redistribution of authority. The first violin may speak first, yet the cello is quickly drawn into melodic partnership, often answering or dovetailing rather than merely underpinning. This is one of the movement’s quiet innovations: Mozart treats “bass line” as “second melodic line,” a compositional stance that becomes clearer the more closely one listens to how phrases are handed from upper to lower register.
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Formally, the movement aligns with sonata-allegro practice, but its rhetoric is less about dramatic contrast than about re-voicing. The exposition’s themes invite recombination: small rhythmic cells and scale figures circulate through the ensemble, and the development can be heard as an exercise in instrumental re-orchestration—who holds the melody, who supplies the counter-singing inner line, who carries the harmonic story. In this sense, the movement participates in the late Mozart tendency to make “texture” itself a bearer of narrative.
II. Andante (A major)
The Andante in A major is the quartet’s emotional center: a movement that sings with operatic poise but never becomes sentimental. Its expressive power lies in equilibrium—melody shaped as if for voice, harmonies that lean momentarily into shadow, and accompaniment figures that feel less like “support” than like a second layer of speech.
Here the cello’s special status becomes especially telling. Mozart frequently places it where it can cantare (sing), either by giving it the tune outright or by letting it share the long line in duet-like textures. The result is not merely “a prominent cello part,” but a new kind of quartet sonority: warmer, lower-centered, and subtly more “orchestral” in blend—yet still intimate.
III. Menuetto: Allegretto – Trio (D major)
The minuet returns to D major with courtly grace, but it is not a simple gesture of sociability. Mozart’s minuet writing in the late 1780s often contains a double meaning: a dance exterior masking an intricate play of balance and accent.
The Trio is the movement most often cited for its cello prominence, and for good reason: Mozart effectively re-stages the ensemble so that the lower string can act as a lyrical protagonist [6]. What is striking, however, is how he does this. The cello’s line is integrated into a chamber texture that remains genuinely four-part; the other instruments do not simply “accompany,” but provide a lattice of counterpoint and harmonic implication that makes the cello’s singing feel earned rather than decorative.
IV. Allegretto (D major)
The finale’s Allegretto continues the quartet’s preference for agility and wit over Sturm und Drang. Its brilliance lies in conversational propulsion: themes are built to travel, to be passed, to be re-accented when they land in a different register. The cello again enjoys moments of melodic foreground—especially in passages where Mozart lifts it above its customary harmonic station—yet the true virtuosity is collective, requiring finely calibrated ensemble articulation.
One can hear in this finale a broader late-classical debate about quartet style: whether the genre’s highest seriousness must be grounded in dense counterpoint and dramatic conflict, or whether an “easy” surface can host a more radical rebalancing of voices. K. 575 makes a persuasive case for the latter. The movement’s apparent ease is, in practice, an advanced compositional achievement: lightness produced by exactness.
Reception and Legacy
The “Prussian” quartets occupy an unusual place in Mozart’s quartet output. They come after the six “Haydn” quartets (1782–1785) and the Hoffmeister Quartet (K. 499), yet they do not simply extend Haydn-esque argumentation; they suggest, instead, what a late Mozart quartet might become when lyricism and timbral re-imagination take precedence over overt dialectic. Modern scholarship has even framed these works as pointing “towards a new aesthetic” of the string quartet—one concerned with blended textures, vocality, and re-weighted instrumental roles [7].
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The dedication to Friedrich Wilhelm II remains central to how the quartet is programmed and discussed, but perhaps its deeper legacy lies elsewhere: in how it makes the cello’s “promotion” feel aesthetically inevitable rather than merely occasional. Later quartet repertory—especially in the early Romantic period—would repeatedly explore richer bass singing and the notion that the lower instruments carry not only harmony but character. K. 575 does not “invent” this, but it models it with a Classical clarity that remains instructive for performers.
In performance history, K. 575 has become a touchstone for ensembles that prize blend and long-line phrasing over brilliant edge. Its interpretive challenge is to preserve the music’s ease while revealing its compositional sophistication: the hidden counterpoint, the delicate redistribution of conversational weight, and the way Mozart turns a patron’s presumed taste (a cellist king) into a structural principle for quartet writing.
Partition
Téléchargez et imprimez la partition de String Quartet No. 21 in D major (K. 575) — the first “Prussian” Quartet sur Virtual Sheet Music®.
[1] Wikipedia — overview, dating (June 1789), Berlin context, and identification as String Quartet No. 21 in D major, K. 575.
[2] Digitale Mozart-Edition (Mozarteum) — Mozart to Michael Puchberg, Vienna, 1789 (commission for six quartets; only three completed; contextual letter).
[3] Wikipedia — ‘Prussian Quartets’ entry noting Mozart’s catalogue description of K. 575 ‘for His Majesty the King of Prussia’.
[4] Otto Jahn (Project Gutenberg) — 19th-century biographical tradition concerning payment/gifts for the Prussian quartets (useful as reception-history anecdote, not primary documentation).
[5] Neue Mozart-Ausgabe / Digital Mozart Edition — editorial commentary (English PDF) on Mozart’s string quartets and the Prussian set (dates; stylistic/genre remarks).
[6] Earsense — interpretive notes highlighting the cello’s soloistic prominence (especially in Trio and finale) within K. 575.
[7] Cambridge Core — book chapter on Mozart’s ‘Prussian’ quartets and their late quartet aesthetic (K. 575, 589, 590; dates and interpretive framing).