"The above variants, along with those among the multiple readings of
numerous other pieces, provide convincing evidence for certain practices. Those who were commissioned to gather a collection of motets and related pieces were free to add one or even two voices to an existing Tenor-Duplum pair. Conversely, they were free to dismantle a piece for three or four voices and present it as one or more pieces for fewer voices. Usually, a piece for three voices was reduced by omission of the Triplum, while a piece for four voices lost either its Quadruplum or its Quadruplum and Triplum. The scribes occasionally even entered a Duplum or a Duplum with Triplum without Tenor. With respect to texts, scribes were free to enter a motet without its
text and give the music as a clausula or even as a discant passage in an organum, just as they could enter a motet with a text other than the original one. Conversely, they must have felt free to add a text to a Tenor-Duplum pair that had started out as a clausula or a discant passage. To a certain extent, moreover, an existing text and its music were subject to variation, and we often have no way of knowing whether the change was made deliberately or by mistake. Those who performed motets, and that probably included creators of motets, had similar freedoms. All of this strongly suggests that the modern respect for the "authentic" form had no parallel among those who transmitted motets to us."