Franz Xaver Süßmayr

Franz Xaver Süßmayr (also spelled "Süssmayr", born Schwanenstadt, Austria, 1766; died Vienna, 17 September 1803) was an Austrian composer. He is often remembered for finishing Mozart’s Requiem which Mozart had not finished when he died.
His father was a sacristan and teacher. His mother died when he was 6, and he left home at 13. He went to Kremsmünster to study in a Benedictine monastery. 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.
After 1787 he became a student of Salieri in Vienna. In 1792 he also became the vice-director and composer at the Kärntnertortheater.
He helped Wolfgang Amadeus Mozart by copying out the music for "La clemenza di Tito" and "Die Zauberflöte" in 1791. In the same year Mozart died. He had not finished composing his Requiem. Süssmayr finished composing it and handed the completed work to Constanze, Mozart’s widow.
He composed Singspiele (German operas with spoken dialogue), and became Kapellmeister at the National Theater From this time until 1800, he was very successful and popular on the Viennese music scene. However, he became ill with tuberculosis and had to stop work. He died three years later in 1803.