Johann Baptist Wanhal was born on 12 May 1739 at Nechanice in Bohemia, into a Czech peasant family and into serfdom. His first training came from his family and from local musicians — the organist Anton Erban was the mentor he valued most — and he was strong enough on violin and organ early on to earn a living as a village organist and choirmaster; he was also taught German, which any musical career in the Habsburg lands required. At twenty-one his patron, Countess Schaffgotsch, brought him to Vienna in her train, and he established himself quickly teaching singing, violin and piano to the high nobility and conducting his symphonies for patrons including the Erdődy family and Baron Isaac von Riesch of Dresden. Riesch paid for a journey to Italy in 1769 to learn the Italian style; Wanhal met Gluck in Venice and Florian Gassmann in Rome, and returned in 1771 to Vienna rather than to Dresden. He died in Vienna on 20 August 1813.

Mozart, Haydn, Beethoven and Schubert all held his music in regard, and he was an accomplished player himself — a proficient organist who also played violin and cello. He is said to have studied with Carl Ditters von Dittersdorf in 1762–63, though the two were born the same year, and around 1785 he took the cello in the string quartet party that also seated Haydn, Mozart and Dittersdorf. The Italian journey is the only evidence of him writing opera: he may have set the Metastasio libretti Il Trionfo di Clelia and Demofonte, alone or with Gassmann, but the music is lost and nothing can be judged. Claims that he became deeply depressed or insane after returning from Italy are probably overstated. His name is spelt many ways — Wanhall, Vanhal, Van Hall — and the modern Czech form Jan Křtitel Vaňhal is a twentieth-century coinage.

Sources:

• https://en.wikipedia.org/wiki/Johann_Baptist_Wanhal
• https://www.wikidata.org/wiki/Q450670