The Missa ad fugam is a musical setting of the Ordinary of the Mass by the composer Josquin des Prez, dating from the early 16th century.
[2] Hallmark techniques of Josquin's mature style are only sporadically present, and even the melodic construction occasionally displays a certain awkwardness.
[3] Uniquely for Josquin, the Missa ad fugam seems to have undergone revision, possibly at the hands of the composer himself.
[4] One late manuscript transmits the mass with minor modifications to the Kyrie and Gloria, and also entirely rewritten Sanctus and Agnus Dei.
; Jesse Rodin and Joshua Rifkin considers it spurious, while its authenticity is strongly defended by Peter Urquhart.