Franz Xaver Süssmayr
Franz Xaver Süssmayr (German: Süßmayr; sometimes written in English as Suessmayr; 1766 – September 17, 1803) was an Austrian composer, most famous for his completion of Wolfgang Amadeus Mozart's Requiem.
Early life 
He was born in Schwanenstadt, Upper Austria, the son of a sacristan and teacher (who spelled the name Seissmayr, reflecting the Austrian pronunciation). His mother died when he was 6, and he left home at 13. He was a student and cantor in a Benedictine monastery (from 1779 to 1787) in Kremsmünster. When his voice changed, he became a member of the orchestra as a violinist.
The abbey performed operas and Singspiele, so he had the opportunity to study the operas of Christoph Willibald Gluck and Antonio Salieri. He composed a number of stage works and a good deal of church music for the abbey.
Association with Mozart 
He became (after 1787) a student of Salieri in Vienna. In 1791 he assisted Wolfgang Amadeus Mozart as a copyist with La clemenza di Tito and Die Zauberflöte and is presumed to have written the secco recitatives in the first. Their relationship was close and playful, to judge by surviving letters to Constanze, whom Süssmayr accompanied to Baden.
For many years he was also thought to have been a student of Mozart, but there is reason to think that the notion of such a relationship was concocted by Mozart's wife Constanze in order to legitimise his completion of Mozart's Requiem. During Mozart's last days, it is possible that they discussed his Requiem, and Süssmayr took on the task of completing the piece upon his death and did so, turning it over to Constanze within 100 days of Mozart's death. Süssmayr's version of the score is still the most often played, although several alternative versions have been written.
Süssmayr also composed a rondo for Horn based on a draft composed in 1791 by Mozart. A comparison between Mozart's draft and Süssmayr's version reveals that Süssmayr used very little of Mozart's material. Süssmayr's rondo also makes use of a plainchant melody, and one explanation of this is that the melody was copied out by Mozart while he was composing the Requiem, which Süssmayr later mistook as material for the rondo. It was included in a piece assembled as Mozart's Horn Concerto No. 1.
Later career 
In 1792 he also became the vice-director and composer at the Kärntnertortheater. On commission for Emanuel Schikaneder, he composed an unsuccessful opera, Moses oder der Auszug aus Ägypten, which premiered May 4, 1792. He was more successful with Der Spiegel von Arkadien, which played across Europe in 1794, also in a Schikaneder production. This success led to his appointment as Kapellmeister at the National Theater in charge of German opera production.
From this time until 1800, he was very successful and popular on the Viennese music scene. However, after that time, his declining health due to tuberculosis led to decline in his career. He had to beg the theater director to stage his last work, List und Zufall.
His marriage plans came to nothing because of his premature death, which occurred in Vienna in 1803. Like Mozart he was buried in an unmarked grave in the St. Marx cemetery.
His works include the following:
- Two masses
- Two requiems
- Seven offertories
- A gradual
- A magnificat
- Nicht mehr als sechs Schüsseln
- Moses oder der Auszug aus Ägypten
- Der Spiegel von Arkadien
- List und Zufall
Of special note may be the clarinet concerto he most probably wrote for Mozart's clarinetist Anton Stadler, because it was scored for the basset clarinet. Recordings of the work by Dieter Klöcker (on Novalis) on "normal clarinet" and by Thea King (on Hyperion) in a reconstructed version for basset clarinet by Michael Freyhan are available.
- Hausner, H.H. (1964). Franz Xaver Süßmayr. Vienna.
- Wlcek, W. (1953, printed 1978). Franz Xaver Süßmayr als Kirchenkomponist (Dissertation ed.). Vienna.
- Wolff, C. (1991). Mozarts Requiem.
- Duda, E. (2000). Das musikalische Werk F. X. Süßmayrs.
- Freyhan, Michael: "Towards the Original Text of Mozart's Die Zauberflote" in The Journal of the American Musicological Society Summer 1986 #2, pp. 355–380
- Freyhan, Michael: "Rediscovery of the 18th Century Scores and Parts of 'Die Zauberflote' showing the Text Used at the Hamburg Premiere in 1793" in Mozart Jahrbuch 1997, pp. 109–149
- Lorenz, Michael: "Süßmayr und die Lichterputzer. Von gefundenen und erfundenen Quellen", in Mozart Jahrbuch 2006
- Franz Xaver Süßmayr, Concerto Movement in D-major, Dieter Klöcker, English Chamber Orchestra on Novalis 150 061 2
- Franz Xaver Süßmayr, Concerto Movement in D-major, Thea King, English Chamber Orchestra on Hyperion CDA66504
- Website about Süßmayr
- Free scores by Franz Xaver Süssmayr at the International Music Score Library Project