Parody fantasia on the first part of the Gloria (semibreves 1-15) of the Mass by Lupus Hellinck. The mass is a parody of a work of the same name by the same composer. Valderrabano intabulates the beginning of model, then continues with florid new music interjecting bits of thematic material from the model (see Ward. p 234).
The mass movement begins with paired imitation, but Valderrabano continues with free polyphony, whose inner proportions are achieved through non-imitative techniques: long mellifluous harmonized melodies, use of opposite motion in consequent phrases, diminution over cantus firmus type movement, similar motion but not strictly imitative, successions of modulating cadences etc. Only two motivic themes have been isolated, but these are not rigid or representative; just those focused upon through imitation 3 is the inversion of the tail of Lupus tail to theme 1. 4 is a little more recurrent.

C.f. RISM 1532/5, Mass nº 3