The Missa brevis K.140 (Anh. 235d = No. 5) occupies a special position in that it comes close to a pastoral mass, a type not otherwise represented in Mozart’s mass oeuvre. As in no other setting of the Ordinary, songlike, graceful melodies predominate; only the main part of the Credo and the first section of the Agnus Dei stand out with their serious, solemn mood.

New, important evidence for the work’s authenticity has come to light through the discovery of old parts that were written at a time in which a false attribution of another composer’s work to Mozart would not have been possible: a copy at Kremsmünster Monastery, which according to Altman Kellner was written in Salzburg “ca. (soon after) 1770”, and a copy from Heilig Kreuz Kloster, Augsburg, of which thirteen parts contain autograph markings by W. A. Mozart. The master’s hand is unmistakable.