String Quartet No. 6 in B♭ major, K. 159 (Milanese Quartet)
ヴォルフガング・アマデウス・モーツァルト作
Mozart’s String Quartet No. 6 in B♭ major (K. 159) was composed in Milan in early 1773, when the composer was only seventeen. The last of the six so-called “Milanese” quartets (K. 155–160), it offers a particularly striking twist on the Italian three-movement quartet: a dramatic, minor-key central movement cast not as an Adagio, but as a compact sonata-allegro.
Background and Context
In the winter of 1772–73, Wolfgang Amadeus Mozart (1756–1791) returned to Italy for the final time with his father, Leopold, spending an extended period in Milan. Among the products of this stay is a group of six string quartets (K. 155–160) commonly known as the “Milanese” quartets—works that stand close to the genre’s origins, when the quartet still overlapped with the divertimento tradition and Italian chamber styles more than with the mature, four-movement, conversational quartet associated with Joseph Haydn [1].
As an Amazon Associate we earn from qualifying purchases.
K. 159 is sometimes overlooked because it belongs to this “early” phase, before the ambitious cycles Mozart would later write in Vienna and dedicate to Haydn. Yet it deserves attention precisely as a document of stylistic transition: a teenage Mozart absorbing Italian taste (clarity, tunefulness, quick rhetorical contrasts) while experimenting with more consequential forms and darker expressive color than one might expect in a light three-movement design [1].
Composition and Dedication
Mozart composed String Quartet No. 6 in B♭ major, K. 159 in Milan in 1773 [2]. It is the sixth and final quartet in the Milanese set (K. 155–160), written when Mozart was sixteen to seventeen years old [1]. No specific dedication is securely attached to K. 159 in the standard reference tradition, and the set as a whole is generally understood as occasional chamber music shaped by local performance expectations rather than as a public “statement” cycle on the later Viennese model.
Instrumentation (standard string quartet) [2]
- Strings: violin I, violin II, viola, violoncello (basso)
Sources for the Milanese quartets are comparatively strong for such early chamber works: autograph manuscripts for K. 155–160 are associated with the Staatsbibliothek zu Berlin holdings, and the quartet is transmitted in later printed editions (including the Neue Mozart-Ausgabe) [2].
Form and Musical Character
Like the other Milanese quartets, K. 159 follows the Italianate three-movement plan (fast–slow/contrast–minuet), rather than the later Classical four-movement layout [1]. The distinctive feature here is that Mozart places the work’s most dramatic argument at its center.
Movements [2]
- I. Allegro (B♭ major)
- II. Allegro (E♭ minor)
- III. Menuetto (B♭ major)
I. Allegro
The opening Allegro presents Mozart in a mode of elegant, outward-facing chamber rhetoric. Textures often favor clear melodic leadership (frequently in the first violin) supported by comparatively straightforward inner parts—an approach consistent with the quartet’s roots in earlier ensemble writing. Even so, the music already hints at Mozart’s instinct for “theatrical” pacing: phrases are set up to invite sudden turns, and cadences tend to arrive with a performer’s sense of timing rather than with purely schematic regularity.
II. Allegro (E♭ minor)
The center of gravity lies in the second movement, an Allegro in the minor mode—E♭ minor—an unusually charged key area for an early string quartet, and unusual also because Mozart does not treat the middle movement as a slow cantabile episode [1]. In fact, K. 159 is singled out within the Milanese set for placing a “fiery” sonata-allegro movement in the middle, intensifying contrast and tightening the work’s dramatic trajectory [1].
For listeners, this movement is the quartet’s best argument for reappraisal. The gesture is bold: Mozart compresses a serious, developmental argument into a space where convention often expected lyric repose. The effect is almost operatic—tension without the “release” of an Adagio—and it throws the surrounding B♭-major movements into sharper relief.
III. Menuetto
The final Menuetto restores social poise and tonal daylight. Rather than serving as a mere light tag, it functions as a stabilizing conclusion after the central disturbance, reaffirming B♭ major with courtly grace. In the context of the three-movement Italian plan, ending with a minuet can feel deceptively modest; here, it reads as a structural solution—Mozart re-balances the quartet after having risked so much expressive weight in the middle.
As an Amazon Associate we earn from qualifying purchases.
Reception and Legacy
K. 159 has never competed in fame with the “Haydn” quartets of the 1780s, nor with later showpieces of quartet craft such as String Quartet in D minor, K. 421 or String Quartet in C major, K. 465 (“Dissonance”). Its legacy is subtler: it illuminates how quickly Mozart learned to bend inherited genres toward drama and contrast, even before the quartet became a central vehicle for his compositional ambition.
Modern access to the work is aided by the survival of early sources and the availability of reliable editions, including the Neue Mozart-Ausgabe score (listed among the principal modern scholarly resources for the quartet) [2]. For performers and listeners, K. 159 rewards attention as more than juvenilia: it is a concise, sharply characterized work whose unusual minor-key, fast central movement offers a glimpse of the mature Mozart’s dramatic imagination arriving early—already active, already impatient with the expected script.
[1] Wikipedia — overview of the Milanese Quartets (K. 155–160), including the note about K. 159’s unusually fiery sonata-allegro middle movement.
[2] IMSLP — String Quartet No. 6 in B-flat major, K. 159: instrumentation, movement list, and publication/source notes including NMA listing.