Mozart wrote the Missa brevis in B flat major K. 275 in 1777. In keeping with the tradition of the genre, the movements are short and succinct. Mozart sometimes even further compresses the work by having different textual passages sung simultaneously. The orchestral scoring is also accordingly concentrated. Alfred Einstein described the expressive content of the mass as “intimate, lyrical, almost private” and characterized it on the other hand as “a work full of delicacy and conspicuous polyphony and, above all, of chromatic agitation and boldness.” The autograph of the work is no longer extant. Franz Beyer’s Urtext edition is based on one of the most important sources of this work.