From Sketch to Completed Work
The Keyboard Concerto in B flat major, K. 450
During the years 1782 to 1785—a period that coincided with a great vogue for public and private concert giving—Mozart was in great demand in Vienna as a composer, performer, and teacher. The intensity of his performance activity during Lent alone is scarcely to be believed; he played somewhere almost every evening for weeks on end. Most of these performances included one or two of his own keyboard concertos, by which he could present himself to his public as, simultaneously, composer, keyboard virtuoso, and orchestra leader.
During this four-year period, Mozart also composed twelve lapidary keyboard concertos, began two others, and wrote new finales for two more. Although complete manuscripts do not exist for all of Mozart’s compositions, documentation for the Keyboard Concerto in B flat major (K. 450) is especially rich. For K.450, there are brief sketches, longer drafts, completed manuscripts, first editions, Mozart’s own comments, and early reviews. This depth of documentation makes K. 450 a fruitful case study on Mozart’s compositional process.
Sketch of the beginning of the Finale
This sketch for the beginning of the Finale of K.450 shows how Mozart sometimes captured his musical ideas on paper. Early in 1784 Mozart had an idea for the refrain of a piano concerto finale. Taking a leaf of music paper on which he had previously drafted the beginning of an otherwise unknown choral fugue in C, he jotted the concerto idea on the empty top staff. The red notation on the transcription page represents Mozart's second thoughts.
Multiple, later hands appear on this sketch leaf, providing insight into the history of this manuscript’s survival after Mozart’s death. In the top margin Constanze Mozart's second husband, Georg Nissen—who in the late 1790s helped her to catalogue Mozart's musical estate—wrote "By Mozart and in his hand." In the left margin and between staves 2 and 3, Maximilian Stadler, a friend and chief assistant in the effort to turn the estate to cash, wrote "NB / Beginning of an 8-voice fugue." In the upper right margin an unknown hand correctly identifies the piano concerto finale.
Fair-Copy Full Score
Wolfgang Amadeus Mozart. Facsimile of the beginning of the Finale of K. 450 from the autograph fair-copy full score. This manuscript is owned by the Herzogin Anna Amalia Bibliothek, Weimar.
When completed, the full score of a concerto served as the source for a copyist to extract a set of parts, which Mozart used for his performances. Mozart sometimes had AN EXTRA SET of parts made for his sister or one of his best students (for instance, Barbara Ployer or Josepha Auernhammer) or a paying patron. In the present case he also apparently had a business arrangement with the Viennese music-copying firms of Lorenz Lausch and Johann Traeg to sell sets of parts, which were advertised in the Wiener Zeitung.
Constanze Mozart sold the autograph scores of the keyboard concertos to the Offenbach music publisher Johann André in 1799-1800, and gave Mozart's own sets of parts to their pianist-composer younger son, Franz Xaver (W. A. Mozart fils); the latter are unfortunately lost.
Mozart’s Thematic Catalogue
The title of Mozart's "Catalogue of all my works from the month February 1784 to the month [ ] 1[ ]" reveals that he expected to live into the 19th century. Precisely why he began this catalogue is unknown. The first three entries are the piano concertos, K. 449, 450, and 451. The entry for K. 450 reads: "the 9th of February. / A keyboard concerto. Accompaniment: 2 violins, viola and basso. -- (2 oboes, 2 horns ad libitum.)" The ad libitum orchestration permitted Mozart to perform his concerto with as few as four instruments or as many as a full classical orchestra, depending on the occasion. When Constanze sold the catalogue to Johann André, their contract stipulated that he would publish an edition of it, which he did in 1805.
Subscribers to Mozart's Lenten concerts, 1784
Briefe Wolfgang Amadeus Mozarts mit Originalbriefen in Lichtdruck, ed. Erich H. Müller von Asow. Salzburg: Zentralinstitut für Mozartforschung an Mozarteum, 1942.
Mozart and his family left posterity an extraordinary body of correspondence, which provides much of what we know about his life and career. In a letter of March 3, 1784, for instance, he bragged to his father about 22 public and private concerts he was then in the midst of presenting. Some days later he sent his father a list of the subscribers to his own concert series on three successive Wednesdays—a list that reads like a who's who of the Austrian nobility. Mozart's new keyboard concertos, K. 449, 450 and 451, were performed at these three concerts. His father noted that the Viennese piano teacher, Georg Friedrich Richter, had reported the concertos' success. Mozart replied on May 26: "The concerto whose praises Herr Richter sang is the one in B flat… Both concertos [K. 450 and 451], I maintain, will make you sweat, however the one in B flat trumps the one in D in the matter of technical difficulty."
The original list is owned by the Library of the Mozarteum, Salzburg.
Guide to Performing Mozart’s Keyboard Concertos
August Eberhard Müller (1767-1817), Anweisung zum genauen Vortrage der Mozartschen Clavierconcerte hauptsächlich in Absicht richtiger Applicatur. Leipzig: Breitkopf & Härtel, [1796].
Published guides to the performance of specific works were almost unknown in the 18th century, when the repertory was constantly changing and new music was the order of the day. A. E. Müller (1767-1817), a Kapellmeister in Leipzig between 1794 and 1810, was principal flutist in the Gewandhaus Orchestra, organist at the Nicholaikirche, and from 1804, cantor at the Thomaskirche. His wife, Elisabeth Catherina Rabert, performed Mozart's piano concertos as soloist with the Gewandhaus Orchestra. This "Instruction on the True Manner of Performing Mozart's Keyboard Concertos, Principally with Regard to Correct Fingering" was probably jointly authored by the couple. The publication demonstrates that Mozart's concertos were already on their way to becoming "classics."
On the other hand, however, that the subsequent volumes covering the rest of Mozart's piano concertos never appeared suggests that sales of vol. 1 may have been poor. This copy is in the Library of Congress, Washington, D.C.