Leopold Kozeluch

This composer is rendered in New Groves as: Kozeluch [Kotzeluch, Koželuh], Leopold [Jan Antonín Ioannes Antonius], which makes for a mouthful of options! Since the only bold bits are plain 'Leopold Kozeluch', without diacritical markings and with all spelling variations and secondary names marked optional, we're opting to catalogue him in that simplified way! This puts us -and the New Groves- at odds with Wikipedia, however, which insists on using the “Leopold Koželuch” variation, which isn't even offered by New Groves! He is, however, listed as 'Leopold Kozeluch' at the IMSLP free music scores website, and there you can see the front pages of several of his scores such as this one, from the Clarinet Concerto No. 1:

It's clear from that example that the name 'Kozeluch' has provenance! Incidentally, he was actually baptised Jan Antonín, but was using the name 'Leopold' by no later than age 26, to distinguish himself from his older cousin who was also called 'Jan Antonín'.

Anyway, he's listed as a 'Bohemian composer' in New Groves and a 'Czech composer' in Wikipedia: he was born in 1747, so the designation as 'Czech' is completely anachronistic, of course. His birth-town was Velvary, which is just 25km north-west of Prague and he would therefore definitely count as a Czech composer these days. He received a basic music education in Velvary before studying music in Prague with his cousin and, later, with František Xaver Dušek. He had his first ballets and pantomimes performed in Prage in 1771-8 to some acclaim, leading to give up his day-job as a law student and devote himself full-time to composition. He moved to Vienna in 1778 and rapidly became known as an excellent pianist, teacher and composer. Three years later, he felt established enough in Vienna to turn down the post of court organist to the Archbishop of Salzburg, recently vacated by one Wolfgang Amadeus Mozart. Mozart's death in 1791 caused Emperor Franz II to similarly offer him Mozart's positions at court, which he duly took up at double Mozart's salary: Kammer Kapellmeister (music director) and Hofmusik Compositor (composer). He would remain in the positions until his death in 1818. His compositional output tailed off after this as his teaching and court work took precedence.

Kozeluch's output is extensive: around 400 compositions in all, including around thirty symphonies, twenty-two piano concertos, two clarinet concertos, twenty-four violin sonatas, sixty-three piano trios, six string quartets, two oratorios, nine cantatas and various liturgical works. His piano works in particular reflected his reputation as a keyboard specialist: he is said to have been a key reason why the piano supplanted the harpsichord around this time. His keyboard sonatas anticipate the 'tragic-pathetic manner of Beethoven and Schubert'. In particular, Kozeluch was writing slow, minor-key introductions to his sonatas some 17 years before Beethoven did so (with his 'Pathétique'), whilst neither Mozart nor Haydn ever did so. On the other hand, his symphonies all date from his early years in Vienna and are generally regarded as pretty weak fare, even by the prevailing standards of the day.

In summary, therefore, Kozeluch was prolific, innovative and well-respected in his day, only plunging into almost complete obscurity at the dawn of the nineteenth century, from whence he has more recently been rescued a little by performances and recordings of some of his more significant compositions.