Michael Haydn wrote the Missa pro defuncto Archiepiscopo Sigismondo, or more generally Missa pro Defunctis, Klafsky I:8, MH 155, following the death of the Count Archbishop Sigismund von Schrattenbach in Salzburg in December 1771. Haydn completed the Requiem before the year was over, signing it "S[oli] D[eo] H[onor] et G[loria.] Salisburgi 31 Dicembre 1771." At the beginning of that year, his daughter Aloisia Josefa died. Historians believe "his own personal bereavement" motivated the composition. Contemporary materials which have survived to the present day include the autograph score found in Berlin, a set of copied parts with many corrections in Haydn's hand in Salzburg and another set at the Esterházy castle in Eisenstadt, and a score prepared by the Salzburg copyist Nikolaus Lang foun