Mozart's name by Mozart scholar Michael Lorenz in the registers of the Lower Austrian Governorship, where in May 1787 "Mozart Wolfgang Amadeus" is referred to as having applied for the return of his written surety for his friend . Other uses of "Amadeus", from immediately after Mozart's death in 1791, are given above. The 19th century saw the gradual victory of "Amadeus" over alternative middle names. The earliest (18th century) biographers of Mozart, such as Friedrich Schlichtegroll and Franz Niemetschek, used "Gottlieb". However, in 1798 the publishing firm of Breitkopf & Härtel began to issue a (partial) Complete Works edition under the
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