Requiem (Mozart)

The Requiem Mass in D minor (K. 626) by Wolfgang Amadeus Mozart was composed in Vienna in 1791 and left unfinished at the composer's death on December 5. A completion dated 1792 by Franz Xaver Süssmayr was delivered to Count Franz von Walsegg, who had anonymously commissioned the piece for a Requiem Mass to commemorate the February 14 anniversary of his wife's death.

The autograph manuscript (acquired by the Austrian National Library in 1831–38) shows the finished and orchestrated Introit in Mozart's hand, as well as detailed drafts of the Kyrie and the sequence Dies Irae as far as the first eight bars of the "Lacrymosa" movement, and the Offertory. It cannot be shown to what extent Süssmayr may have depended on now lost "scraps of paper" for the remainder; he later claimed the Sanctus and Agnus Dei as his own. Walsegg probably intended to pass the Requiem off as his own composition, as he is known to have done with other works. This plan was frustrated by a public benefit performance for Mozart's widow Constanze. Constanze was responsible for a number of stories surrounding the composition of the work, including the claims that Mozart received the commission from a mysterious messenger who did not reveal the commissioner's identity, and that Mozart came to believe that he was writing the requiem for his own funeral.