Wolfgang Amadeus Mozart rapidly maturing composer. Wolfgang met Josef Mysliveček and Giovanni Battista Martini in Bologna, and was accepted as a member of the famous Accademia Filarmonica. In Rome, he heard Gregorio Allegri's "Miserere" twice in performance, in the Sistine Chapel, and wrote it out from memory, thus producing the first unauthorized copy of this closely guarded property of the Vatican. In Milan, Mozart wrote the opera "Mitridate, re di Ponto" (1770), which was performed with success. This led to further opera commissions. He returned with his father twice to Milan (August–December 1771; October 1772 – March 1773) for the composition and premieres
Wolfgang Amadeus Mozart Theme from Mozart's Opera "Die Zauberflöte" (1822), Frédéric Chopin's Variations on "Là ci darem la mano" from "Don Giovanni" (1827), and Max Reger's Variations and Fugue on a Theme by Mozart (1914), based on the variation theme in the piano sonata K. 331; Pyotr Ilyich Tchaikovsky wrote his Orchestral Suite No. 4 in G, "Mozartiana" (1887), as a tribute to Mozart. For unambiguous identification of works by Mozart, a "Köchel catalogue number" is used. This is a unique number assigned, in regular chronological order, to every one of his known works. A work is referenced by the abbreviation "K." or