String Octet in E‑flat major, Op. 20

1Identity & Context

• Full titleOctet for Strings in E‑flat major, Op. 20 (MWV R 20)
• ComposerFelix Mendelssohn (1809–1847)
• Forces4 violins, 2 violas, 2 cellos
• Composedcompleted October 15, 1825 in Berlin. Revised c. 1832–33; the revised version is what is almost always played today.
• Premiereprivately at the Mendelssohn family home on the Leipziger Straße, likely at one of the famous Sunday musicales. First public performance in Leipzig, January 30, 1836.
• Published1832 (Breitkopf & Härtel), dedicated to the violinist Eduard Rietz, Felix's close friend and teacher, who led the first readings. Rietz died young in 1832; Mendelssohn also commemorated him in the slow movement of the String Quartet Op. 13.
• Age of composer16. The octet is the most astonishing teenage masterpiece in the Western canon — not a clever juvenilia but a fully formed, technically fearless work that no adult Mendelssohn would surpass for chamber color.
• Place in outputthe arrival piece. Before it, Mendelssohn had written twelve string sinfonias, some concertos, and promising salon work. After it — and the Midsummer Night's Dream Overture a year later (1826) — he was a composer of international rank. The octet inaugurates the "Mendelssohnian scherzo" idiom he would mine for the next two decades.
• Historical moment1825 is the year Beethoven wrote the Op. 132 A minor Quartet and the Grosse Fuge; Schubert produced the "Great" C major Symphony the next year; Weber's Der Freischütz had premiered four years earlier. Romanticism is fully arrived, but the Classical formal instinct is still load-bearing. Mendelssohn, raised on Bach, Handel, Mozart, and Beethoven through the Berlin Singakademie, synthesizes all of it.
• Instruction on the scoreMendelssohn's preface is famous — "This Octet must be played by all the instruments in symphonic orchestral style. Pianos and fortes must be strictly observed and more strongly emphasized than is usual in pieces of this character." He is telling the players: do not treat this as a double quartet. Treat it as an orchestra of eight.

2Formal Structure

The octet is a four‑movement work lasting about 30–33 minutes.

I. Allegro moderato, ma con fuoco — E‑flat major, 4/4

• Form: full‑scale sonata‑allegro with a very long exposition and a development that earns every bar.
• Proportions: c. 13–15 minutes. The biggest movement.
• Key scheme: I (E‑flat) → V (B‑flat, second theme), development ranging through C minor, A‑flat, F minor, G minor; recap in E‑flat with second theme now in the tonic; coda that rebuilds the opening surge.
• Sectional map:
• Exposition: soaring Violin I theme over tremolando inner voices, rising an octave and a sixth in the first two bars — the signature gesture. Transition through virtuosic passagework. Second theme (bar ~70) in B‑flat, lyrical, in dialogue between violins and violas. Closing group tightens rhythm and drives to a hammered cadence.
• Development: starts quietly, fragments the main theme's leaping head, passes it through inversion and stretto between the eight voices. Builds an immense polyphonic climax.
• Recapitulation: returns with the tremolando apparatus now redistributed (a Mendelssohn fingerprint — he never simply repeats).
• Coda: compressed, ecstatic; the opening leap becomes a fanfare.

II. Andante — C minor, 6/8

• Formthrough‑composed ternary with variation elements. Roughly A — B — A′ with a melancholy, wandering middle.
• Key schemeC minor opening, moves to E‑flat major and A‑flat major for the B section, returns to C minor with a coda that settles onto a Picardy‑inflected resolution.
• Proportionsc. 6–7 minutes.
• CharacterMendelssohn at his most Schubertian — rocking 6/8, sighing suspensions, a sense of overheard private mourning. The cellos open with a walking, shadowed line; violins enter in thirds high above. Unusual among Mendelssohn slow movements for its chromatic restlessness rather than serene hymnody.

III. Scherzo: Allegro leggierissimo — G minor, 2/4, sempre pianissimo e staccato

• Forma single perpetual‑motion arch — not a conventional scherzo‑trio‑scherzo. More like a through‑composed moto perpetuo with contrasting episodes and a disappearing coda.
• Key schemeG minor → tonicizes B‑flat → a long chromatic middle zone through D minor and E‑flat — → returns to G minor → evaporates.
• Proportionsc. 4 minutes. Feels like 90 seconds.
• Famous literary programFelix's sister Fanny Mendelssohn recorded that Felix told her the scherzo was inspired by the Walpurgis Night Dream passage from Goethe's Faust, Part I: > "The flight of clouds and veil of mist / Are lighted from above. / A breeze in the leaves, a wind in the reeds, / And all has vanished."

That single programmatic hint is the key to the whole movement — it ends by vanishing on a pianissimo unison G, the "puff" of wind after which "all has vanished."

IV. Presto — E‑flat major, 2/2 (alla breve)

• Formsonata‑rondo with fugal episodes. Combines a rondo's returning refrain, a sonata's development, and a fugue's imitative rigor — technically astonishing writing for a sixteen‑year‑old.
• Proportionsc. 6–7 minutes.
• Key schemeE‑flat throughout its refrains; the fugal subject is stated successively in cello II, cello I, viola II, viola I, violin IV, III, II, I — a rising ladder of entries climbing from the bottom of the ensemble to the top, eight voices, one after another. Modulations reach C minor and A‑flat before the triumphant return.
• Quotations insideMendelssohn embeds a theme from Handel's Messiah — specifically "And He shall reign forever and ever" from the Hallelujah chorus — which appears in counterpoint against his own subject. He also references the scherzo's main motif in the middle of the finale, a cyclic gesture unprecedented in chamber music of this scale before Beethoven's Ninth.

Macro‑architecture

• Key planE‑flat → C minor → G minor → E‑flat — a descending chain of thirds before the return home. E‑flat is the "heroic/imperial" key (Beethoven's Eroica, Mozart's last symphony, Beethoven's Emperor Concerto), and Mendelssohn places his first major public statement there.
• Thematic linksscherzo returns literally inside the finale. The finale's scalar rush echoes the first movement's opening ascent.
• Narrative arcradiant exuberance → private lament → supernatural flicker → communal triumph. It is, in miniature, the shape of a Beethoven symphony.

3Melodic & Thematic Content

• First movement themea rising arpeggio from E‑flat, leaping up an octave in bar 1, then pushing through B‑flat to higher G — an eleventh of upward span in under three bars. The gesture is what conductors call a "lift": the bow attack, the tremolando floor beneath, and the sheer altitude of the first violin line together create the sense of a curtain flying up.
• Second subjectlyric, in thirds, stepwise, answering the first theme's bravado with sweetness. The move from outward‑ness to inward‑ness inside the exposition is handled with unusual grace for a teenager.
• Scherzo motifa three‑note pickup (short‑short‑long) that never stops. Every phrase in the scherzo is built from micro‑cells of this shape passed between voices like a relay.
• Finale fugue subjecta long‑short‑short‑long‑long pattern with a rising fourth at its head — an ideal imitative subject because its profile stays clear even when stacked eight voices deep.
• Thematic transformationwatch how the Goethe‑inspired scherzo motif is quoted inside the finale at mm. ~70 onward. The flicker of the elves returns in the middle of a triumphant fugue — briefly, almost as a secret — and then the finale resumes.
• Motivic economyless than Beethoven (this is not a work built from a single four‑note kernel) but more than standard early‑Romantic chamber music. Each movement has its own idiom, but motivic fragments cross movements.

4Harmony & Tonality

• Harmonic language: essentially Classical voice‑leading animated by Romantic color. Mendelssohn is not a chromatic radical — he is a chromaticist of the Mozart‑plus‑Bach lineage. Every chromatic chord has a voice‑led reason.
• Notable progressions:
• The C minor slow movement's B section reaches A‑flat major through a mediant side‑slip that is pure early Schubert.
• The scherzo's vanishing ending — a unison G stripped of third and fifth — is harmonically extraordinary: it doesn't cadence, it dematerializes.
• The finale's fugue entries cycle through fifths in a way that echoes Bach's Art of Fugue; Mendelssohn had been studying Bach at home with Zelter for years.
• Cadential patterns: Mendelssohn generally avoids the heavy perfect authentic cadence at structural seams (except at final closure). He prefers elided cadences that keep the line moving — this is why the octet feels breathless.
• Dissonance treatment: conservative by 1825 standards. No emancipation of dissonance; every suspension resolves. The Romanticism comes from register, dynamics, and harmonic color, not dissonance density.

5Rhythm, Meter & Tempo

• First movementsurging 4/4 with tremolando inner voices that function like an orchestra's string tremolo. The rhythmic character is orchestral — Mendelssohn's preface is not hyperbole.
• Slow movement6/8 with a characteristic lilt; the walking bass line in the cellos gives the movement its mournful gait.
• Scherzo2/4 at a tempo that must be flying but never hurried — the crucial marking is leggierissimo (as light as possible). Not prestissimo. Light, not fast. The distinction is the whole interpretive question of this movement.
• Finalealla breve at a presto tempo, with relentless eighth‑ and sixteenth‑note motion. The challenge is articulation clarity through eight instruments at this speed.
• Tempo relationshipseach movement is faster in character than the last — Allegro moderato → Andante → Allegro leggierissimo → Presto. The slow movement is the emotional fulcrum around which the three faster movements pivot.

6Orchestration, Texture & Timbre

This is where the octet is genuinely revolutionary.

• Instrumentation: the double string quartet (4 violins, 2 violas, 2 cellos) was not Mendelssohn's invention — Louis Spohr wrote double quartets — but Mendelssohn refused to treat the ensemble as two quartets in dialogue. He blended the eight instruments as a single orchestra.
• Textural strategies:
• Orchestral tremolando: lower seven instruments sustain tremolando while violin I carries the theme — exactly the texture of an orchestral first movement.
• Antiphonal blocks: violins I–IV against violas and cellos, or odd‑numbered against even‑numbered instruments, producing stereo‑field effects.
• Solo emergence: any of the eight can step forward. In the scherzo, the theme is tossed between voices with such speed that no single player "owns" it.
• Fugal stacking: the finale's rising fugue entries produce an eight‑voice texture that almost no other chamber work of the 1820s dared.
• Dynamic architecture: Mendelssohn's preface insists on orchestral dynamic contrasts. The first movement's exposition has true fortissimo climaxes; the scherzo must stay pianissimo almost throughout, which in eight players is physically harder than playing loud.
• Timbral innovation: the scherzo's color — leggierissimo staccato in all eight instruments, piano throughout — invented a new sound. It is the direct ancestor of the Midsummer Night's Dream scherzo (1826, one year later), the scherzo of the Scottish Symphony, and ultimately the gossamer scherzo tradition that runs through Berlioz, Saint‑Saëns, and Ravel.

7Emotional Arc & Dramaturgy

• Movement Ipublic, extroverted, radiant. A young man announcing himself. The climaxes feel won, not asserted.
• Movement IIinward, grieving, almost Schubertian in its acceptance of sadness. The most personal music in the work.
• Movement IIIotherworldly. This is music about seeing something (the Walpurgis vision) and then having it disappear. It is a piece of enchantment — Mendelssohn's first great fairy scherzo — and its emotional effect is the thrill of glimpsing something you can't quite catch.
• Movement IVcommunal jubilation, learned counterpoint, the quotation of Handel's "And He shall reign forever" — an affirmation not just of the key of E‑flat but of the composer's place in a tradition.

The overall arc is triumphant in the classical sense. Brightness → private sorrow → fantasy → collective joy.

8Historical Significance & Influence

• What was newnobody had written chamber music of this orchestral scope, thematic integration, and contrapuntal density before — certainly not at sixteen. Spohr's double quartets are elegant but stay in the salon; Mendelssohn's Octet is a symphony's ambition in chamber dress.
• The "fairy scherzo" lineagethe Op. 20 scherzo invents a genre. Every Mendelssohn scherzo afterward — the Midsummer, the Scottish Symphony's second movement, the Piano Trios — descends from it. So do Berlioz's Queen Mab scherzo, Bruckner's scherzo writing (indirectly), and much of Ravel.
• Receptionthe octet was slow to be heard in public (the first public performance was eleven years after composition), but within the Mendelssohn circle it was immediately recognized as extraordinary. Its reputation grew steadily through the 19th century, was dimmed by the anti‑Mendelssohn turn of the late Romantic and early modernist period (Wagner's infamous 1850 essay, Shaw's dismissals), and was fully re‑established after WWII.
• Place in canonnow regarded as one of the greatest chamber works of the 19th century, and the single greatest work by a teenage composer in the Western tradition.
• Relationship to contemporaneous worksin 1825 Beethoven was writing the late quartets a few hundred miles away. The octet is not late‑Beethoven in spirit — it is closer to the Mozartian–Bachian synthesis Mendelssohn had absorbed through Zelter. But the ambition, the four‑movement integrity, the cyclic finale quotation — these are Beethovenian gestures.

9Performance Practice & Notable Recordings

• Double‑quartet vs. orchestral: ensembles still debate whether to play one‑on‑a‑part (chamber style, eight individual voices) or with a small string orchestra (fully realizing Mendelssohn's orchestral preface). The chamber reading is now standard, but the preface is unambiguous about the character Mendelssohn wants: symphonic.
• Scherzo tempo: the single hardest interpretive call. Too fast and the staccato articulations blur; too slow and the magic evaporates. The tradition ranges from ~2:40 (fastest) to ~4:30 (slowest).
• Repeats: the first‑movement exposition repeat is usually observed in modern recordings. Pre‑1970 recordings often omitted it.
• Landmark recordings:
• Academy of St Martin in the Fields Chamber Ensemble (Philips, 1979) — eight players, symphonic reading, gloriously sprung. Iona Brown leading.
• Vienna Octet (Decca, 1966) — warm, burnished, very Viennese; a benchmark of old‑world tone.
• Mullova / Dumay / Caussé / Wang / etc. — "ad hoc" international octets (multiple, DG / Philips) — featured players (e.g. the Ozawa‑led New Japan Philharmonic Mendelssohn project, or the Marlboro Festival recordings) bring individuality to every line.
• Nash Ensemble (Hyperion, 2004) — a deeply considered chamber reading, textures scrupulously balanced.
• Academy of St Martin / Hausmusik London (Virgin/Erato, period strings, 1990s) — period‑instrument reading that restores the articulation and the transparency; the scherzo becomes almost terrifyingly clear.
• Isaac Stern + members of Guarneri Quartet & others (Sony, 1982) — legendary live‑ish recording with Stern leading a dream team; extravert and thrilling.

10Listening Guide

Timings reference a standard ~32‑minute recording. Your version may vary by ±2 minutes.

• 0:00 — Curtain up. The violin I leap; tremolando blanket underneath. Listen for how high the first violin goes and how the other seven instruments function as an orchestral pad.
• 2:30–3:30 — Second theme enters, lyrical, in dialogue. Notice the sudden softening of texture.
• 6:30–9:00 — Development. The main theme fragments; listen for imitative entries passed through the ensemble. The polyphonic climax around minute 8 is the first movement's peak.
• ~11:00 — Recapitulation: the opening leap returns but with the accompaniment redistributed. Same surface, new interior.
• ~13:30 — Movement ends; a breath.
• 13:30–20:30 — Andante. The cellos' shadowed opening line. At ~16:00, the major‑mode middle section floats in. Around 18:30, the C minor opening returns, darker. Listen for suspensions and sighing figures.
• ~20:30 — Scherzo. Pianissimo throughout. Listen for: (a) how the motif is relayed across all eight instruments so quickly you can barely track it; (b) the central sustained passage where the flicker becomes more harmonic and mysterious (~22:00); (c) the ending — a pianissimo unison G that evaporates. This is the Walpurgis vanishing. Don't miss it — conductors sometimes let it slip away in under a second.
• ~24:30 — Finale. Count the fugal entries: cello II enters alone, then cello I, then the violas, then the violins in sequence. All eight voices eventually stack.
• ~27:30 — The scherzo motif returns inside the finale. A secret flicker in the middle of the triumph. Catch it — it's the cyclic gesture that ties the whole work together.
• ~28:30 — Handel's "And He shall reign" surfaces in counterpoint (if you know the Messiah, you'll feel the shiver).
• ~31:00 — Coda. The ensemble converges on E‑flat; the final cadence is earned, not merely arrived at.

First‑listen focus: movements I and III. The extroversion and the magic. Deeper re‑listen focus: the Andante (for emotional depth) and the finale's counterpoint (for architectural marvel).

11Must‑Listen Tracks

1. Scherzo (III. Allegro leggierissimo). If you listen to nothing else, listen to this. It is one of the greatest four minutes in the 19th‑century string literature, the moment where Mendelssohn invents an entire expressive genre in real time. A sixteen‑year‑old writes the Walpurgis scene of Faust as music and then, with the final pianissimo unison G, makes it vanish — and the technique, the scoring, the vanishing ending, all of it, is the template for a century of fairy music. It is also the most immediately gripping movement: light, uncanny, over before you know it, demanding a re‑listen.

Recommended recording for this movement: Academy of St Martin in the Fields Chamber Ensemble / Iona Brown (Philips, 1979) — the staccato is impossibly clean, the dynamic is truly pianissimo, and the disappearing ending is perfectly calibrated. Runner‑up: Hausmusik London on period instruments, for uncanny transparency.

2. First movement (I. Allegro moderato, ma con fuoco). If you have a second 13 minutes. This is the movement that announces Mendelssohn as a world composer. The opening theme's upward leap, the tremolando orchestral texture underneath, and the long polyphonic development earning the recapitulation: it is the clearest case in the repertoire of a teenager writing fully mature music.