# What is the harmonic function of this?

What is the harmonic function of the boxed beat in the fourth measure?

• What sort of answer are you after? The function of that chord (effectively D#7) is to modulate to G# major. It's a diminished chord, which adds a bit of spice. Commented Jul 17, 2019 at 21:53
• Not quite...see below Commented Jul 18, 2019 at 0:49

The chord in the box is a "French" augmented sixth chord (A-C#-D#-F##), which resolves to G# major as V/C#m. The crucial voiceleading is the augmented sixth A-F## resolving to the octave on G#.

(This is a good example of why we need double sharps; the interval sounds like A-G, but it is not a seventh! If it were, the "G" would have to fall back to F#.)

The C#m chord doesn't show up, but it's implied. Instead we get iv/C# = ii/E, heading chromatically [C#-C-B] to V/E across the page turn.

Full analysis:

I - ii6 - F6/5 - V/vi - (vi) - ii - V - I

• Ah, you just beat me to it; I was in the middle of editing! After sitting down with this example again, this makes much more sense with the G-sharp major chord. Good work! Commented Jul 18, 2019 at 0:55
• Does anyone recognize the aria? It sounds like Verdi, but I can't place it... Commented Jul 18, 2019 at 1:03
• "O mio Fernando" from Donizetti's La favorita. Commented Jul 18, 2019 at 1:21