reliable a guide to the actual counterpoint as the theoretical principles on which all writers agree.
(Particularly important to the theorists, of course, is the principle of occursus, which the transcription
does its bit to reinforce.)
Of course it could be argued just as logically that in the absence of a precise rhythmic notation, the
manuscript alignment was the only possible—and therefore an indispensable—guide to the counterpoint.
Yet a glance at Fig. 5-3 will suffice to show that the alignment was not a matter of great concern to the
copyist. Even more basically, to argue that the alignment was meant to guide performance is to assume
that the piece was transmitted primarily in writing, and that its performers read it off the page. The
opposite assumption, that the piece was transmitted orally and performed from memory (with the notation
having little more than the status of a souvenir or an artobject), accords better with what we know of
medieval practice.
EX. 5-8A Cunctipotens genitor setting, from Ad organum faciendumEX. 5-8B Cunctipotens genitor setting, from Codex Calixtinus