After his father's early death, Moscheles settled in Vienna in 1808. His abilities were such that he was able to study in the city under Albrechtsberger for counterpoint and theory and Salieri for composition. At this time he changed his first name from "Isaac" to "Ignaz". He was one of the leading virtuosi resident in Vienna during the 1814–1815 Congress of Vienna and it was at this time that he wrote his enormously popular virtuosic "Alexander Variations", Op. 32 for piano and orchestra, which he later played throughout Europe. Here, too, he became a close friend of Meyerbeer (at that time still a piano virtuoso, not yet a composer) and their extemporized piano-duets were highly acclaimed. Moscheles was also familiar with Hummel and Kalkbrenner. Among the virtuosi of the 1820s, Hummel, Kalkbrenner, Cramer, Herz and Weber were his most famous rivals.