How to analyze a chord from Beethoven sonata no 8 (Pathetique)

Question

Looking at a chord towards the end of the development in measure 169, beat 2, spelled C♯-E-A♭ over the G pedal.

How would you analyze this in the context of the harmonic progression at that point?

The best I can come up with is that the C♯/E is a non-harmonic tone leading up to D-F-A♭, a diminished chord with subdominant function. So the core of the progression is then V-ii(dim)-♭VI-V.

What I'm wondering about is whether the C♯/E/A♭ has a function of its own in the progression. I might call it a ♭ii(dim) but that doesn't quite feel right.

Answer 1

The whole passage is essentially a linear elaboration of V^♭9. Let's "de-broken-chord" it: it fairly leaps to the eye what Beethoven is doing here when you see the voices.

Note that we're getting a big A♭-G appoggiatura in the top voice, but the inner voices are marching up and down in minor thirds between the chord tones of the dominant (marked "+") in such a way as to sort of tonally center on G: passing tones E/C♯ to suggest an approach from the dominant's dominant, E♭/C to suggest the tonic minor.

Answer 2

The best way to look at it is as you stated as the C♯ and E as non harmonic tones leading to the D and the F respectively. It could be looked at as a variation of a Neapolitan 6th where the 3rd is minor instead of major that goes to the ii^o instead of V especially since if you look at it as different enharmonic equivalents of D♭, F♭, and A♭ which make D♭m. While this is a possibility keeping the C♯ and E as non-harmonic tones that lead to ii^o makes more sense, but you can see where the idea for this harmony comes from.

Answer 3

For the upper Bass staff Passing tones stepwise of the voices with unmatched rhythm and staggered resolution. This resolving to a normal G major chord by bar 173. How does Beethoven get away with it? The compass of the uppermost voices spans B natural to B natural with the passing tone movement between the two B's. All the notes having accidentals are merely harmonic coloration. What justification might I have for referring to the inner voices as passing tones? (Thanks to user16935's post the melodic lines are clearly filtered). The low G's (2nd stave) throughout the entire passage suggest to me that Beethoven intends to establish G major while the upper voices veer slightly to notes adjacent to the notes of a G triad.