Brief Analysis- Mozart Piano Sonata in C Major, K. 545 III Mvt.
Roman Numeral analysis of m. 41-48 in the relative minor---key of a minor:
m. 41-43: i64 V7 i64
m. 44: V42 V6
m. 45: i iio i6
m. 46-47: iv7, N6 V7
m. 48: i
In Mozart’s Piano Sonata in C Major III, most of the work is in the key of C Major but the excerpt given in measures 41-48 is featured in the relative minor key of a minor. In this excerpt, the use of the Neapolitan chord in m. 47 creates a surprising change in the harmony because the Bb does not fit chromatically into the diatonic scale. The N6 is approached by a iv7 chord in m.46 with a descending sixteenth melodic line above a prolonged i in the tenor and a bass line that moves both upward and downward to the D and F in m. 47 to create the N6. The N6 resolves to a V7 on the second beat in m.47 which then leads to the tonic i in m. 48. This harmony of iv7-N6-V7-i follows the progression T-PD-D-T, where the N6 functions as the PD. The Neapolitan also follows the standard voice-leading, where the b2 is in the highest voice and resolves to a 1 (Bb to A in m.47) and the b6 is in one of the lower voices (in this case, the tenor voice) and the b6 resolves to the 5 (F to E in m. 47).