About this work
Mozart entered the Fantasia in C minor, K. 475 into his "List of All My Works" on May 20, 1785. In the same year, the piece was published in Vienna together with the Piano Sonata in C minor under the collective designation "Op. 11." In this version, the Fantasia serves as an introduction to the sonata, its improvisatory character placing the structural weight upon the sonata itself.
The Fantasia is one of very few works Mozart composed in C minor during his years in Vienna. Because of the formal freedom traditionally associated with such pieces, the composer was able to produce in the Fantasia a notably expressive example of keyboard music; in contrast to the prescriptions of traditional forms, the Fantasia instead draws upon Mozart's intuition and supreme sensitivity as a composer and pianist.
The opening theme makes it clear that this is no unfolding sonata form: although the melodic material is symmetrical, the harmony avoids the relationships common to the first themes of sonata movements. The unusual changes in harmony blur the primacy of the tonic and wander in such a way that later resolution seems impossible. The dominant does arrive during a passage of repeated, right-hand chords, but this has little effect since the tonic was never firmly established. This material returns at the end, but the result is symmetry rather than resolution.
The Fantasia unfolds through four tempi -- Adagio, Allegro, Andantino, and Più Allegro -- which help to delineate is sections. Each change of tempo signals the introduction of new material. The Adagio departs from C minor immediately and ventures as far away as B minor over repeated figures in the left hand. The Allegro begins with a wobbling idea in the right hand that focuses on D major, eventually giving way to an area of continuous modulation. For the most part, the ensuing Andantino is so stable that it could almost be performed alone, but it, too, gives way to further modulation and the continuous C minor of the Più Allegro, which emphasizes rapid, expressive figuration.