# How Do These Decorative Chords Contribute to Diatonic Modulation in Aldwell and Schachter's Example?

I'm studying diatonic modulation via example (e) in Unit 26 of "Harmony & Voice Leading" by Aldwell and Schachter and need some clarification. The progression moves from an F major to an E7 - Am cadence. While I grasp the overall concept of leading to an authentic cadence, I'm struggling to distinguish between the functional chords driving the modulation and the decorative ones.

Could someone please explain the inclusion of non-essential chords within this progression? I'm interested in understanding the progression as a whole, as each chord contributes to the progression's flow and harmonic richness.

Many thanks.

• What leads you to believe any of the chords are non-essential, since that factor isn't mentioned in the exercise's description. Nov 8, 2023 at 0:43
• @Aaron great point--I guess I thought it was implied, since they say that the options they present are not the only ones and because they don't explain every chord. I see they refer to the I, V, II and/or IV chords, but they dont elaborate on the use of inversions as seen, for example, in the 4th and 6th chords in the progression Nov 8, 2023 at 0:48
• Okay, I think that clarifies things, for me at least. Thanks. Nov 8, 2023 at 0:51

`VI ii[6-5] V[4-2] i[6] ii[6] Cad[6-4] V[7] i`.
Clearly the final `V-i` is essential, since it most strongly states `A minor`. There is a weaker `V-i` between chords 3 and 4, but, by nature of the inversions involved, and it's placement between two predominant chords on either side (chords 1, 2 and 5, 6), it doesn't really serve a cadential function. Instead, one can interpret the first six chords as a prolonged predominant.
3. Chords 7 and 8 are essential, comprising the cadence confirming `A minor`.
4. The remaining chords are non-structural, comprising an extended predominant transitioning from the `VI` chord to the `Cad[6-4]` chord.