This triplum text, which begins and ends with the same verbal allusions as the motetus, was explicitly
fashioned as a sort of rhetorical double or echo to it:
Our piece is now a doubly prosulated clausula, more commonly known as a double motet. (Ex. 7-1 is
a transcription of it.) And that is both the fascination and the enigma of the medieval motet. In its
developed form, the one Grocheio knew and loved, the genre was “polytextual,” which is to say it had as
many texts as it had voices over the Gregorian tenor. Before we get any deeper into the question of
polytextuality, however, there is another matter, also well illustrated in Fig. 7-3, to investigate.
FIG. 7-3 Double motet on Ex semine (Bamberg, Staatliche Bibliothek, Lit. 115, fols. 15 v–16). The triplum and motetus voices
are notated side by side (note the capital initial E’s). The tenor is beneath the motetus (to its left is the end of the tenor for the
preceding motet).