Sent to his close friend Baroness von Waldstätten, it declares that he will need to get married within two days in order to save his future wife, Constanze, from the scandal of being dragged out of his house by the police.
At the time it was written, Constanze was known to be cohabiting under the same roof as Mozart, which prompted her mother, Cäcilia Weber, to send in the police to reclaim her daughter from the composer’s house to save her reputation.
This prompted Mozart to declare the only solution is for him to marry Constanze the next day - or indeed the same day if at all possible. The couple went on to marry on August 4, 1782.
The letter, estimated at £300,000-500,000 at the Exceptional Sale on July 6 during Classic Week, comprises two pages and was sent while he was in Vienna in summer 1782.
Thomas Venning, head of Christie’s books and manuscripts, London, said: “Mozart letters are scarce at auction and it is hard to think of any iconic historical figure where you have an equivalent unfiltered insight into such an important and private moment. The letter has always been in private collections and has not been seen by the public or scholars since 1989.”
An autograph music manuscript by Mozart for the opening 15 bars of the second movement (Andante) of the Serenade in D major for orchestra was sold at Christie’s London in December 2022 for a hammer price of £100,000. In June 2017 Christie’s New York sold an autograph letter by Mozart signed to his father for $260,000 (then around £203,000).
Sotheby’s took £280,000 in May 2018 for a Mozart manuscript of an unfinished Allegro in G for piano and four hands, consisting of two autograph leaves and comprising just 98 bars in all.