Despite his illness, Schubert continued to compose one work after the other. Starting in the spring of 1828 he composed many works, among them a Mass, various piano pieces, many songs that were printed posthumously in a collection titled Schwanengesang, as well as the three final piano sonatas. In September of 1828 his health took a turn for the worse and his doctor advised him move out of the city, so he moved into his brother Ferdinand's house which was in the suburbs of Vienna. Up until the very last weeks of his life Schubert continued to compose until he no longer was able. Schubert finished his last piano sonata on September 26, 1828. He died November 19, 1828. He was but 31 years old.
The last three piano sonatas were not published until ten years after Schubert's death. Schubert's piano sonatas were neglected during most of the 19th century. His other music came to be revered, but the common opinion about his piano sonatas were that they were inferior to his other works. Even Robert Schumann, to whom the publisher of the last sonatas dedicated the works, was of this opinion:
Whether they were written from his sickbed or not, I have been unable to determine. The music would suggest that they were. And yet it is possible that one imagines things when the portentous designation, ‘last works,’ crowds one’s fantasy with thoughts of impending death. Be that as may, these sonatas strike me as differing conspicuously from his others, particularly in a much greater simplicity of invention, in a voluntary renunciation of brilliant novelty—an area in which he otherwise made heavy demands upon himself—and in the spinning out of certain general musical ideas instead of adding new threads to them from phrase to phrase, as was otherwise his custom. It is as though there could be no ending, nor any embarrassment about what should come next. Even musically and melodically it ripples along from page to page, interrupted here and there by single more abrupt impulses—which quickly subside.An exception to this 19th century opinion was Brahms, who was fond of the sonatas and studied them intensely. The sonatas continued to be neglected until early in the 20th century when a handful of pianists like Artur Schnabel championed the works and played them in recitals. The last piano sonata is in 4 movements:
I. Molto moderato - No doubt one of the reasons for the negative attitudes about this piano sonata is the inordinate length of the first movement. This first movement averages about twenty minutes if the exposition repeat is taken, which is as long as many complete sonatas. Because of the length of this movement some pianists do not take the exposition repeat, thus shortening the work. The exposition repeat became somewhat of an option with later composers, but with Schubert it is essential. There are many things that differentiate the later sonatas from the earlier ones, one of which is the long, lyrical themes that take time to unfold, which contribute to the length of movements. The first theme of this movement begins with a theme that is calm and lyrical. This theme is interrupted by a trill on G-flat, a most unusual interruption that sounds foreign harmonically, almost sinister. The theme resumes after this intrusion and is then slightly developed by means of a key change to G-flat. Schubert modulates back to the tonal center of B-flat for the rest of the theme. Schubert then introduces what amounts to a long transition to the second main theme of the movement. He begins this transition material in the key of F-sharp minor, moves the home key and then the second theme makes its appearance in the key of F major. More transition material appears before the music of the first ending of the exposition appears, music that is unique and not heard again in the movement. The exposition is repeated verbatim, except for new transition material that leads to the development section. The development section is extensive and modulates quite often to many different keys. The development section comes to an end with the repeat of the mysterious trill on G-flat. The recapitulation repeats the exposition material with the obligatory changes in key to the home key of B-flat major. A short coda brings back the first theme along with the trill on G-flat and the movement ends in B-flat major.
II. Andante sustenuto - Schubert has more harmonic surprises in the second movement. It begins in C-sharp minor, a key that played a role in the development section of the previous movement. The theme is a sad one that is intensified by the accompaniment that covers the bottom, middle and top of the keyboard. A contrasting middle section begins in A major and does its share of harmonic roaming. The first theme returns with some slight alterations. The mood is still sad, but the alterations in the accompaniment have given it an added tension. The theme modulates and finally comes to rest in C-sharp major and the movement ends quietly.
III. Scherzo: Allegro vivace con delicatezza - The scherzo is in B-flat major and lightens up the mood of two preceding brooding movements. The trio section is in B-flat minor and Schubert creates rhythmic instability by tying notes over the bar line and accenting notes in the left hand, sometimes on the beat, sometimes off the beat. The scherzo is repeated and with a very short coda it comes to a close.
IV. Allegro ma non troppo – Presto - A movement in sonata form with three main themes. The first is in B-flat major and begins with an octave on G. This is repeated each time the first subject is played. The second theme is more mobile and in F major. The third theme begins with a sharp double forte outburst in F minor. After the third theme is played through, material from the first theme leads directly to the development as the exposition is not repeated. The development section deals with the first theme only. The three themes are repeated in the recapitulation, and the work ends with a coda that is marked presto.