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.

[2] 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 found in Munich.

[3] The mass is scored for the vocal soloists and mixed choir, two bassoons,[4] four trumpets in C, three trombones, timpani and strings with basso continuo.

"[5] Sherman also recommends interpreting the Andante maestoso of the Dies Irae at "a pulse of = MM.

"[11] Pauly notes specific parallels between the two requiems: rhythmic similarities in the setting of the Introit, Quantus tremor and Confutatis maledictis sections, the use of a plainchant melody in the setting of Te decet hymnus, and the subject of the fugue in Quam olim.