Sigismond Thalberg was born on 8 January 1812 at Pâquis near Geneva. He said himself that he was the illegitimate son of Moritz, Prince of Dietrichstein, and Maria Julia Bydeskuty von Ipp; his birth certificate names Joseph Thalberg and Fortunée Stein of Frankfurt. Little is documented of his childhood; he may have been brought to Vienna at ten — the same year the ten-year-old Liszt arrived — and by his own account was at the first performance of Beethoven’s Ninth Symphony on 7 May 1824. His first teacher is unknown, though Baroness von Wetzlar, his putative mother and a fine amateur pianist, may have started him. He studied with Ignaz Moscheles in London in the spring of 1826 and first played there publicly on 17 May; from 6 April 1827 he appeared regularly in Vienna in a mainly classical repertoire of Hummel, Mozart and Beethoven concertos and chamber music. He died on 27 April 1871.

His Op. 1, a fantasy on themes from Weber’s Euryanthe, was published by Haslinger in 1827, and he built a career on operatic fantasies of that kind, becoming one of the century’s most celebrated virtuosos. Mendelssohn and Chopin, who met him in Vienna in 1830, thought his technique astonishing; the ten-year-old Clara Wieck, who heard him in Leipzig in May 1830 and had played Field and Hummel to him two days earlier, noted his playing as clear, precise, strong and expressive. Counterpoint studies with Simon Sechter in the early 1830s put canon and fugue into his fantasies — the Grande fantaisie et variations sur ‘Norma’, Op. 12, published in 1834, contains both — and although Schumann criticised that piece, he praised the plainer style Thalberg turned to next, including the 2 Airs russes variés, Op. 17.

Sources:

• https://en.wikipedia.org/wiki/Sigismond_Thalberg
• https://www.wikidata.org/wiki/Q347871