I'm trying to understand this simple progression in the middle of Paganini's 4th caprice.
This seems like I-?-I-V7-I in Eb major, but I am unable to figure out what the function of the second chord is. I know it is Ebdim7 (or Adim7 or Gbdim7 or Cdim7).
- There is some nice voice leading from the A-nat to the B-flat in the third chord, which suggested it is a secondary leading chord of some sort, but the third chord is Eb, which doesn't make sense: io7 - I??
- Perhaps the second chord could be viio7/V7, but this doesn't seem to make sense if there is a I chord between the viio7/V7 and the V7.