Beethoven's Immortal Beloved: Initial Analysis of Piano Sonata 28, Opus 101
After reading Marek's account I took another look at the first of the five so-called late-Beethoven sonatas, Opus 101, which Beethoven had dedicated to that same Dorothea von Ertmann.
The very first sentence of the sonata stymied me as much as it had previous music analysts until, after much trial and error, I stumbled on using a short text to guide me through its labyrinthian twists and turns. Employing the motto "Du, du, Liebste, mein / You, you, Love, of mine" for the first two measures, I could understand not only this first sentence (a four measure antecedent followed by a twenty-one measure consequent) but more importantly that not only the first sentence, but the entire four-movement sonata, was built on the motif contained in these first two measures.
Only years later did I read in Schindler's "Beethoven as I knew him" that using an appropriate text was exactly the devise Beethoven advised using for the decoding of a difficult to understand passage.
Ibes, Willem (Wim), "Beethoven's Immortal Beloved: Initial Analysis of Piano Sonata 28, Opus 101" (1995). Music Lectures. 6.