The project Nissen Online, currently under preparation, offers the first critical edition of the most comprehensive Mozart biography of the early 19th century. The Biographie W. A. Mozart’s: Nach Originalbriefen, Sammlungen alles über ihn Geschriebenen, mit vielen neuen Beylagen, Steindrücken, Musikblättern und einem Fac-simile, was published in early 1829 by the renowned publishing house Breitkopf & Härtel in Leipzig.
The biography which was prepared by Georg Nikolaus Nissen (1761–1826), Danish diplomat and second husband of Constanze Mozart (1762–1842), provided for the first time the comprehensive correspondence of the Mozart family. But besides the letters, a large part of the book is based almost literally on contemporary writings about Wolfgang Amadé Mozart, mostly without citing its sources and authors.
The goal of the edition is to reveal the structure of the text by unveiling the manifold sources Nissen used when writing the biography: These comprise primary sources, such as original letters and documents of the Mozart family, secondary sources, such as contemporary literature about Mozart, and original text written by Nissen and other contributors to the edition. All identified text passages will be marked up and commented, primary and secondary sources will be linked to digital resources.