After Mozarts Death
His wife, Constance
After the death of her husband, Constance established contact with publisher Johann Anton André with a view to publishing Mozart's compositions. Only two of the six children from her marriage to Mozart survived - Carl Thomas and Franz Xaver Wolfgang. They soon began to demonstrate they had their own innate musical gifts. In 1809, Constance Mozart married the Secretary to the Danish Legation, Georg Nikolaus Nissen, who, in addition to historian and librarian Friedrich von Schlichtegroll, was one of the first to write a Mozart biography.
It soon became clear that the two sons had their own innate musical gifts.
Carl Thomas concluded his business studies in Livorno and then, thanks to the intercession of Joseph Haydn, a great admirer of his father, turned his attention to the study of music. In 1810, however, he also abandoned this path and commenced a career in the civil service.
His younger brother, Franz Xaver Wolfgang, known as W. A. Mozart (the son), received instruction from Johann Nepomuk Hummel, Georg Joseph Vogler, Antonio Salieri and Johann Georg Albrechtsberger, becoming an important composer and pianist in his own right.
In the 19th Century
In the second half of the 19th century, the academic world showed growing interest in the works of Wolfgang Amadeus Mozart. The first edition of a "Chronological and Thematic Catalogue of all of Wolfgang Amadé Mozart's Musical Compositions", better known as the "Köchel-Verzeichnis", was published by Ludwig Ritter von Köchel in 1862 through Breitkopf & Härtel in Leipzig. On the initiative of the International Mozart Foundation, this same publishing house presented the Old Mozart Edition between 1877 and 1910. Commissioned by the International Mozarteum Foundation, Bärenreiter-Verlag Kassel began publication of the New Mozart Edition in 1955, the bulk of the work having been completed by 1991.