And here we enter my field! So: the fundamental questions are: has a Tenth ever existed, even in the form of a sketch? Why would B. have thought of a new symphony in 1824-1827? What are the sources? When was it eventually conceived? What remains today of this composition? First of all, let us give the floor to Luigi Della Croce (Della and not Dalla, otherwise the old man gets really angry, as I have been able to experience firsthand!)
The "phantom" of the tenth symphony-----
The project to compose a tenth symphony emerges from a letter by Beethoven dated March 18, 1827, eight days before his death, addressed to Moscheles. It is a response to the latter's letter, which had announced the happy news of the sending of one hundred pounds by the Philharmonic Society, the recipient of the Ninth Symphony. Beethoven asks Moscheles to communicate to the English institution that he will reciprocate the generous grant, considering it as an advance on the earnings from a much-anticipated concert in London for his benefit, with a "new symphony, which is already sketched in my desk, or a new overture or anything else the Society might like".
There are also direct testimonies from Anton Schindler and the amateur violinist Karl Holz, both of which were made many years after the events. According to the former, Beethoven, on February 27, after his fourth operation, still deluding himself that he could recover (whereas the doctors had lost all hope), expressed the desire to resume work on the tenth symphony, the structure of which he had described to him on another occasion. For his part, Holz recounted that Beethoven had played the complete tenth symphony to him on the piano, based on sketches indecipherable to everyone except the author, and, according to a second version, that he had heard him perform the tenth from memory limited only to the first movement, consisting of "a gentle introduction in E-flat major followed by a powerful allegro in C minor". In the notebooks of notes relating to the years 1825-27 and all of which ended up in Schindler's possession, the latter underlined in pencil some themes that should be identified with the "raw" material of the tenth. In an exhaustive article on the subject, published in the Beethoven-Jahrbuch, 1977, Robert Winter points out how meager and vague these melodic ideas are, whose destination for a symphony remains to be proven. The sketches of what Schiudici claims to be an andante in A-flat major and a scherzo in C minor with a trio in C major would not coincide with Holz's descriptions and, in any case, Beethoven did not mark anything in the margin that could suggest their belonging to the plan of a symphony. On the other hand, at the bottom of a fragment in D minor, which Schindler did not take particular consideration of, Beethoven wrote the words "finale of the first piece-orchestra". This would be, according to Winter, the only indisputable [fragment known of the tenth, the only surviving trace of a design that Beethoven certainly cherished for years and which, on his deathbed, still occupied his mind.
For the skeptical Winter, his epistolary declarations to Moscheles are not decisive, as he was prone, partly for commercial reasons and partly due to innate optimism, to proclaim almost ready or completed compositions that might not even be "in the works". As for the accounts, retroactive and partly contradictory, of the two cited contemporaries, they should be taken with the widest benefit of the doubt.
To conclude his investigation into the supposed existence of a more or less advanced scheme of a symphony after the Ninth, Winter condenses his perplexities into a picturesque simile, which can be summarized as follows: if Beethoven were to appear before a court under accusation of having followed through with a project for a tenth symphony, the verdict would surely be an acquittal, at least for insufficiency of evidence.
This restrictive conception was however refuted in no. 1 of "Music & Letters" in 1985 by another Anglo-Saxon scholar, Barry Cooper, for whom the received sketches offer elements of information that have hitherto escaped analysis: if correctly interpreted, they can support the hypothesis of a tenth symphony project already reasonably advanced, at least regarding the first movement. In particular, there would be no apparent contradiction between the "accounts" of Schindler-Holz and the fragments in question, which would almost entirely refer to an allegro in C minor with an introduction in E-flat major. Many of the arguments put forward by Cooper seem solid. However, it remains a stretch to derive from an evident sketch of a scherzo and trio the main subject of the allegro, as well as to deny this theme any relationship with an equally phantom and only"
prospective overture on the name Bach. For Cooper, the so-called "secure" fragment would feature three flats in the key signature instead of one and would therefore be perfectly compatible with a piece in C minor.
Long post. Let's divide it. I will respond personally in the evening-------------