Biamonti 608 – Fugue Sketches, February – August 1815 (Nottebohm, Volume II, page 319).

They bear the annotation: “Bei allen Fugen Piano e Forte” (“In all fugues, piano and forte”)

New findings from the Beethoven Music Research Center (July 2024): These sketches are located in Kraków at the Jagiellonian Library, specifically in the pocket sketchbook known as Mendelssohn-Stiftung 1. Nottebohm, in Chapter 34 of his Zweite Beethoveniana, highlights several fugue themes found within the notebook:

1. Page 19, line 1 – in E major, written only in pencil; without the beginning of the answer.
2. Page 24, line 6 – in F minor, transcribed in ink; without the beginning of the answer.
3. Page 42, lines 6–8 – in D major, transcribed in ink; without the beginning of the answer.
4. Page 42, line 9 – in C major, only in pencil; without the beginning of the answer.
5. Page 54, lines 3–4 – in F minor, transcribed in ink; with the beginning of the answer. In the countersubject, in my opinion, the natural sign on D is missing, since we should have modulated to C minor.
6. Page 56, lines 1–4 – in E minor, transcribed in ink; with the beginning of the answer.

As we’ve just seen, some of these fugue themes are written in pencil (numbers 1 and 4), while others have been traced over in ink to make them more visible (numbers 2, 3, 5, and 6). Only number 1 is not labeled as a fugue; the others are all presented as fugue themes, probably intended for some pupil (perhaps his nephew?).