Porpora, Durante, Pergolesi and Vinci were all pupils of Greco. It’s possible that Domenico Scarlatti was too (and that Alessandro Scarlatti was one of his teachers), but there appears to be no firm evidence.
He met Hummel in Warsaw when he was 18, and Czerny in Vienna a year later. He spent much of his adult life in Paris, where he befriended Berlioz, Bellini, Heller, Hiller, Mendelssohn, Delacroix, Hugo, Liszt, Dumas, Franchomme, Balzac and Heine; also Sand, whom he was not initially attracted to, but then spent 10 years with. Paris was a home for other Polish exiles like Mickiewicz. He met Schumann in Leipzig and Dickens during a 7-month stay in London. He only visited Carlyle for an hour, but told his wife that their piano was out of tune.
Süssmayr studied under Salieri. He helped Mozart as an assistant and copyist, and completed Mozart’s unfinished ‘Requiem’ after his death. The relationship appears to have been jovial, and may not have been a teacher/student one as generally supposed. Schikaneder commissioned two operas from him, one successful, the other not.
Schubert studied under Salieri in Vienna. He met the poet Mayrhofer aged 17, forming a close friendship despite their utterly different characters. Weber and Beethoven were passing acquaintances, though Beethoven acknowledged Schubert’s genius. Bauernfeld was Schubert’s close friend for the last 4 years of his short life, providing words for his music and translating ‘Who Is Sylvia.’ Bruchmann was also among his inner circle, using his house for Schubertianas, and being arrested with Schubert and Senn by police hunting subversives.
Reicha, Czerny and Salieri taught him (Hummel charged too much). Whether Beethoven really kissed the 12-year-old’s forehead is not known. He met his friends Mendelssohn and Chopin aged 20, Chopin becoming a professional rival. He met Hiller in Paris, was friendly with Lamennais, Andersen, Heine, Ingres and Baudelaire, and became close to Berlioz, Schumann and Wagner. He championed Berlioz and Wagner, although he began to find Wagner (who had married his daughter) somewhat repulsive. He taught Siloti and Friedheim free after taking holy orders. Saint-Saëns was a lifelong friend, Sand an intimate (not a lover).
Ravel proved uninterested in his work. He had already met Milhaud when his piano teacher introduced him to Satie, Casella and Auric. Satie told him to laugh off his rejection by the Conservatoire for being too radical; Stravinsky, who became a lifelong friend, arranged to have a piece of his published when he heard the story. Bartók wrote expressing interest in his work. He composed settings for texts by his friends Apollinaire, Jacob, Cocteau and especially Éluard. Cocteau (mentor and lifelong friend) planned a forged letter to get him out of military barracks. 40 years after befriending Prokofiev, he dedicated his last major piece to him.
Hiller studied in Weimar under Hummel, where he also met Goethe. As a 15-year-old he met the dying Beethoven in Vienna, and joined Hummel as one of the pallbearers at Beethoven’s funeral, cutting the famous lock of hair from the dead man’s head. As a young composer in Paris, he knew Liszt, Berlioz, Chopin and the Mendelssohns (he was more impressed by Fanny than Felix, and was so close to Berlioz that he willingly gave up his girlfriend to him). Schumann corresponded with him before taking over his former post as music director in Düsseldorf. He belonged to a wide network of Jewish composers and musicians.
D’Indy taught him. He met Debussy while working as a café pianist; a long friendship eventually ended by a misunderstanding. Ravel met him as a student. He told Poulenc, rejected by the Conservatoire and accused of being a disciple, to laugh it off. He collaborated with Picasso, Diaghilev, Massine and Cocteau, with Picabia and Clair, and wrote about his friend Stravinsky’s music. Valadon was briefly his lover, Thomson saw him as his mentor, and Ray’s first readymade was jointly contrived the day they met. Milhaud helped sort through his belongings (25 years’ worth in one room) after his death.
Widor and Massenet (who was fond of him) taught him. Both Debussy and Satie (who was very close to him) gave him original scores. Hofmannstahl collaborated for 8 years, Busoni told him machines would become essential in music, and Strauss, met in the street, helped him get his first pupils. Zadkine, Miró, Artaud and Villa-Lobos were regular Paris companions. Russolo, a friend, understood sound differently. Varèse gave his pupil Jolivet a puppet, and cooked boeuf bourgignon for Miller. Stravinsky called him the Brancusi of music. Parker, awed, followed him on the street without daring to speak (though eventually did).
Waller heard Ellington’s band on their first foray to New York, and persuaded them to try again. Smith influenced his style, and helped him survive. Hodges, Webster, Miley and Blanton were among the most influential of his band-members. Stayhorn impressed him with his composing and arranging skills, and became his closest friend and right-hand man (though he didn’t get given all the credit due). Ellington was godfather to Vian’s daughter, while his friend Grainger tried to tempt him into academia. Fitzgerald recorded his music, while Ibrahim, Mingus, Coleman and Roach all played alongside him.