Sor did it, but forgot to show us,
Now it was done by Mark Delpriora. There is one statement by Sor in his method, just after Example 82, one almost goes by without noticing it. It says:
J'ai été toujours d'opinion que d'arranger tel morceau que l'on voudra pour un instrument qui ne peut le rendre proportionnellement, c'est plutôt le déranger; et qu'au lieu de dire arrangé pour tel instrument, on devrait dire sacrifié à tel instrument. Je joue la fugue à double sujet en si bémol de l'oratorio de Haydn, la Création;
Which I translated as follows:
I was always of the opinion that wanting to arrange such a piece for an instrument that cannot render the music in the same proportions as in the original, is often to discompose it. Instead of saying that the piece was arranged for such an instrument, one should say that it was sacrificed to it. I play on the guitar the B-flat fugue on a double subject in Haydn’s oratorio The Creation,
The double fugue in question is a vocal fugue with full orchestral accompaniment which bring the oratorio to a close. It begins on m. 10, of N° 34, the final chorus in the oratorio, on the words Des Herren Ruhm, er bleibt in Ewigkeit [The praise of the Lord will endure forever]. This is an intriguing statement. Sor specifically says that he plays this fugue. In the present tense. He may have just read through the piano score on the guitar, or he may have actually noted it down on paper. Such a transcription by Sor is not known to exist. So I suggested to Mark to try and see if Sor was just bragging, or if in fact this double fugue, in b-flat, is possible on the guitar. Turns out that it is possible. Mark's transcription will be published very soon. Look for it.
Speaking as a guitarist and composer with several years of experience in choral singing who composed a three-voiced fugue in B flat minor last year (with fully invertible counterpoint, though admittedly with some voice crossing between countersubjects 1 and 2) I can totally believe Sor's claim that he was at one point able to play Haydn's double fugue in B flat from the Creation on the guitar. I happen to love fugues, I happen to love Haydn's music, and I enjoy The Creation. When I get some work lined up and find out where and when this double fugue transcribed for guitar is getting published I will have to see about picking up a copy. Meanwhile I will keep practicing my prelude and fugue in B flat minor, my prelude and fugue in F minor, and my prelude and fugue in C minor. I'll have to get around to composing a fugue in B flat major later on when I have ideas I actually like enough to commit to working on.