Beethoven's musical style
The compositions that Beethoven wrote in his formative period can be generally characterized by the composer's efforts to master the predominant classical language of the period. His works from this period can be subdivided into two, based on the composer's residence. First, various juvenalia, written when the adolescent Beethoven was in residence in Bonn and heavily indebted to the works of contemporaries, especially Mozart and his teacher, Christian Gottlob Neefe. These early efforts can be seen in a set of three piano sonatas and piano quartets (WoO 36) that Beethoven wrote before 1792. The Quartets, for instance, are each specifically modelled after three Violin sonatas Mozart published in 1781 – K 296, 379 and 380 – and Beethoven would later draw upon this familiarity in the composition of several of his own Violin Sonatas.
Leopold Koželuch
Koželuch's substantial output of keyboard compositions reflected the promotion of his reputation as a specialist keyboard virtuoso. Christopher Hogwood argues that Koželuch's keyboard sonatas, especially those which open in minor keys, "substantially anticipated ... the tragic-pathetic manner" of Beethoven and Schubert, and that in them he "created the internationally praised "cantabile" idiom". Hogwood further states that "Koželuch's sonatas are, in the true sense, 'classics'—that is to say, 'models for imitation and study'—and display to perfection precisely those features that theorists required of a sonata at the end of the 18th century. The oeuvre of sonatas spans almost the entirety of Koželuch's career: the first was composed in 1773; the final three date from after 1810. The sonatas cater for different purposes. Some are exhibitionist works; some are simpler; some are cast in a Romantic style that foreshadows Beethoven. In the third category, Koželuch was composing slow minor-key introductions to sonatas as much as 17 years before Beethoven composed his Piano Sonata No. 8 ("Pathetique"), while neither Mozart nor Haydn ever did so. Koželuch's composed his sonatas to be played on the newly emerging fortepiano rather than the harpsichord. The popularity of the sonatas in turn helped to make the fortepiano fashionable.