Prelude (Fantasy) and Fugue in C major KV 394 (383a)
Prelude (Fantasy) and Fugue in C major KV 394 (383a) is a two-piece work by the Austrian composer Wolfgang Amadeus Mozart from 1782.
Prelude
The prelude ( 
measure) begins with an eight-measure adagio introduction : The characteristic here is the diminished seventh character . First begins with a broken C major triad, the continuation of which is continued in the second bar with sevenths. Bars 3 and 4 have a similar character, but are structured in G major and canonical. For the next six bars the motif (broken A major triad) is in the left hand. A triplet run follows in the six other bars. With increasing progress, a motive for complaint in the echo increases. In bar 45 a kind of cadenza appears. The motive for the lawsuit reappears later. Mozart modulates in runs from F minor to C minor and finishes the prelude in the dominant G major.
Gap
In bar andante mastoso, the theme of the three-part fugue consists of two bars and begins in the bass. The middle voice carries the theme in measure 3 a fourth higher. In bar 6 the exposition of the fugue ends with a G major triad. After a three-bar transition you find yourself in the first development in A minor. Meanwhile, Mozart modulates in F major and there is a transition in bars 20/21. Then there is a relaxation in the dominant. In bars 40–47 there is a "third" development in A minor. The reprise-like final section begins in measure 51. The final two bars end in an adagio.