A reviewer writing for the Allgemeine musikalische Zeitung in 1826 described the fugue as "incomprehensible, like Chinese" and "a confusion of Babel".

130, written in 1825; but Beethoven's publisher was concerned about the dismal commercial prospects of the piece and wanted the composer to replace the fugue with a new finale.

Music analysts and critics have described the Grosse Fuge as "inaccessible",[3] "eccentric",[4] "filled with paradoxes",[5] and "Armageddon".

[6] Critic and musicologist Joseph Kerman calls it "the most problematic single work in Beethoven's output and ... doubtless in the entire literature of music",[7] and violinist David Matthews describes it as "fiendishly difficult to play".

But in recent years, Beethoven had become increasingly concerned with the challenge of integrating this Baroque form into the Classical structure.

Beethoven composed this replacement finale while staying at the estate of his brother Johann in Gneixendorf during the late autumn of 1826, and it is the last complete piece of music he was to write.

[18] Stephen Husarik has suggested that the relationships between the keys of the different sections of the fugue mirror what he describes as the wedge-like structure of the eight-note motif that is the main fugal subject, the "contour [that] is a driving force behind the Grosse Fuge".

[19] But Leah Gayle Weinberg writes: "The Grosse Fuge has been and continues to be a problematic subject of scholarly discussion for many reasons; the most basic is that its very form defies categorization.

[21] Some sections of the work follow the strict formal structure of Baroque grand fugues, while others are more freely constructed.

[22] Another similar subject, with syncopated or gapped rhythm (called Unterbrechung in German), appears in a treatise on counterpoint by Johann Georg Albrechtsberger,[23] who taught Beethoven composition.

The opening is shown below: In the course of the Grosse Fuge, Beethoven plays this motif in every possible variation: fortissimo and pianissimo, in different rhythms, upside down and backwards.

This last variation grows increasingly chaotic, with triplets breaking out in the inner voices, until it ultimately collapses – each instrument finishing on a different part of the measure and ending inconclusively on a final fermata, leading to the next section in the key of G♭.

Leonard Ratner writes of this section, "[This] comes as a wonderful change of color, offered with the silkiest of textures, and with exquisite moments of glowing diatonism.

"[29] The polyphony gradually dissipates into homophony, and from there into unison, finally tapering into a dying, measured sixteenth-note tremolo, when the next section bursts out in the key of B♭.

On top of this, Beethoven adds a lilting, slightly comic melody; analysts who see the fugue as a multi-movement work consider this section the equivalent of a scherzo.

This time, though, instead of a silky pianissimo, the fugato is played forte, heavily accented (Beethoven writes f on every sixteenth-note group), march-like.

Abiding faith in the relevance of visionary struggle in our lives powerfully informs the structure and character of the music," writes Mark Steinberg, violinist of the Brentano String Quartet.

"[40] Daniel Chua, on the contrary, writes, "The work speaks of failure, the very opposite of the triumphant synthesis associated with Beethovenian recapitulations.

"[41] Stephen Husarik, in his essay "Musical direction and the wedge in Beethoven's high comedy, Grosse Fuge op.

Sara Bitloch, violinist of the Elias String Quartet, says this sense of struggle informs her group's interpretation of the fugue.

The poet Mark Doty wrote of his feelings on listening to the Grosse Fuge:[45] What does it mean, chaos gathered into a sudden bronze sweetness, an October flourish, and then that moment denied, turned acid, disassembling, questioned, rephrased?

"The attitude of mind in which most people listen to chamber music must undergo a radical change" to understand this piece, wrote Joseph de Marliave in 1928.

Pianist Glenn Gould said, "For me, the 'Grosse Fuge' is not only the greatest work Beethoven ever wrote but just about the most astonishing piece in musical literature.

"[50] Some analysts and musicians see the fugue as a pioneering assault on the diatonic tonal system that prevailed in Classical music.

Robert Kahn sees the main subject of the fugue as a precursor of the tone row,[51] the basis of the twelve-tone system developed by Arnold Schoenberg.

Among the technical difficulties of the piece are difficult passagework, complex cross-rhythms that require exact synchronization, and problems of intonation, where the harmonies pass from dissonance to resolution.

[56] Played with the new finale, the preceding movement, the "Cavatina", a heartfelt and intense aria, is the emotional center of the piece.

A second issue facing performers is whether to choose a "learned" interpretation – one that clarifies the complex contrapuntal structure of the piece – or one that focuses primarily on the dramatic impulses of the music.

[63] Musicologists have tried to explain what Beethoven meant by this: David Levy has written an entire article on the notation,[36] and Stephen Husarik looked to the history of Baroque ornamentation for an explanation.

In early 1826, after Matthias Artaria had published the Op.130 quartet, he informed Beethoven that there had been "many requests" for a piano four-hand arrangement of the Grosse Fuge.