Harmonic Analysis - Coda

The Coda remains harmonically tame, as Beethoven moves toward the ending. The only instance of modal mixture occurs in measure 148 with a III chord. Otherwise, Beethoven uses secondary dominants to set up most of the sub-dominant chords. From measure 157 until the end, Beethoven has many cadential 6/4 chords moving to I. By the end, the final cadence is already the third 6/4 cadence, so Beethoven decides to play in very fast, in eighth notes.