The Piano Sonata No. 14 in C minor, K. 457, by Wolfgang Amadeus Mozart was composed and completed in 1784, with the official date of completion recorded as October 14, 1784 in Mozart’s private catalogue of works.[1] It was published in December of 1785 together with the Fantasy in C minor, K. 475, as Opus 11 by the publishing firm Artaria, Mozart’s main Viennese publisher.