After the death of the legendary composer Wolfgang Amadeus Mozart, his widow, Constanze, remarried in 1809 to Georg Nikolaus von Nissen, a Danish diplomat and passionate admirer of Mozart’s work. This union not only provided stability for Constanze and her children but also set in motion one of the most remarkable efforts to preserve Mozart’s legacy.

Georg Nicolaus Nissen after painting by Jagemann.

Nissen was a man of diverse talents—a poet, amateur musician, and, above all, a devoted supporter of Mozart. His deep respect for the composer led him to compile an extensive biography of Mozart, a monumental work that spanned over 900 pages and was published posthumously in 1829. Nissen’s dedication to this project consumed much of his life, as he meticulously collected documents, letters, and musical scores, often working late into the night.

Yet, Nissen’s efforts went beyond mere biography. He discovered hundreds of Mozart’s compositions hidden in a closet in Constanze’s apartment, which he carefully cataloged and sold, ensuring that these masterpieces would not be lost to history.

Interestingly, Nissen also harbored suspicions regarding the mysterious circumstances surrounding Mozart’s death. In his final years, he pursued a private investigation, corresponding with close friends and seeking to uncover what he believed was a potential murder plot. His determination to reveal the truth was so profound that, in a secret letter to his stepson Wolfgang, Nissen urged him to continue this investigation after his death, warning of the dangers involved and even involving the King of Denmark as a witness to his testament.

Georg Nikolaus von Nissen’s Letter in 1826 to Step-son Wolfgang Xaver
to Expose Mozart’s Violent End 

Image reproduced with permission from the Mozarteum Foundation.

Nissen’s legacy is a testament to his unwavering dedication to Mozart and his relentless pursuit of the truth. Though his final investigation into Mozart’s death remains inconclusive, his contributions to preserving and promoting the composer’s work are invaluable, making him an integral figure in the history of classical music.

To delve deeper into this fascinating story about Georg Nikolaus von Nissen and his connection to Mozart, you can download the full document from the link below.