Both Hasse and Farinelli were Porpora’s pupils, Hasse later becoming a professional rival. Haydn became his valet and accompanist, and said that he learned ‘the true fundamentals of composition’ from him. Metastasio wrote libretti for him during a long and fruitful friendship, the première of one work launching Farinelli’s public career.
The elder Mozart’s genuine achievement resists measurement, not least because he sacrificed his own career to that of his two children. He corresponded with Gellert and was a friend of Wieland. Joseph Haydn told him that his son was ‘the greatest composer known to me either in person or by name.’ Kelly and Attwood visited him with a plan of his son Wolfgang’s for a trip to England, but it didn’t come off. In Paris Leopold made the acquaintance of Grimm, who arranged concerts for the Mozart family (father, daughter and son) and had them introduced at court.
Albrechtsberger was among composers sought out by Kraus on a long visit to Vienna in 1783. Michael Haydn had been a fellow-student, and both Haydn brothers were friends of Albrechtsberger, as also was Mozart, of whom he was very fond. Hummel, Czerny, Moscheles, Weigl and Beethoven were among his pupils.
Kandinsky was his uncle and close friend. Jaspers supervised his PhD, though Kojève spent more time studying Sanskrit, Tibetan and Chinese. Koyré, an early influence, became his university colleague in France (after Kojève lost his fortune investing badly). His famous weekly Hegel seminars were attended by Breton, Bataille, Merleau-Ponty, Lacan, Klossowski, Queneau, Aron, Caillois, and briefly Arendt: Queneau and Bataille becoming close friends strongly influenced by his ideas, Bataille regularly going to eat and drink with him following the seminar. Lévinas and he loved discussing Dostoyevsky together.
Czerny studied under Beethoven, Hummel, Salieri and Albrechtsberger. Chopin and he were admirers of each other’s work, and visited and corresponded frequently. Clementi was a colleague, and Thalberg, Liszt and Heller were among his pupils. Field visited him in Vienna, probably only once.
Da Ponte wrote libretti for a number of Salieri’s operas. Beethoven, Czerny, Liszt, Hummel, Moscheles, Meyerbeer, Süssmayr and Schubert were all students of his – an exceptional list. Gluck was both patron and friend, and Metastasio an acquaintance. Fellow-composers in Vienna included Haydn and Mozart, who collaborated with Salieri on one piece (now lost). There is little evidence of the animosity popularly supposed to have characterised his relationship with Mozart; the fact that Mozart engaged him to teach his son may indeed happily suggest that it is a fiction.