This publication offers a source-critical edition of Mozart’s fragmentary “Requiem” as well as an alternative to the traditional Sussmayr version. It makes it possible to perform 1) the fragment, identified in print in both the score and the parts, 2) the authentic sections left incomplete by Mozart, now in a stylistically appropriate orchestration, and 3) those sections missing entirely in the fragment, newly added in Mozart’s idiom taking into account historical additions by Sussmayr and Eybler.

When completing the fragment, the editor drew on comprehensive comparative and analytical studies of Mozart’s church style and compositional workmanship. The influence of Handel and Bach manifested in his final years, particularly in the “Requiem” fragment, is taken into account in those sections requiring completion or fresh composition.

At two points readers may choose between alternative movements (or sections), since proceeding from Sussmayr’s historical version, two divergent options cannot be weighed against each other but each one may well reflect Mozart’s intentions: the “Lacrimosa” may end with or without “Amen” fugue, and the “Sanctus” may begin in the customary D major or in D minor. Above all, this makes it possible to retain the B-flat major “Hosanna” from Sussmayr’s autograph, a movement which, until now, has not been appreciated as compositionally flawless.