FIG. 8-2 Ars Nova notation: the four signatures.BACKLASH
Just as the technology-minded theorists of the “Ars Nova” represented the first selfconscious avant garde
faction in European literate music, so they inspired the first conservative backlash. It is found in the
seventh and last book of the mammoth Speculum musicae (“The mirror of music”), at 521 chapters the
largest of all medieval music treatises, completed around 1330 by Jacobus (or Jacques) de Liège. The
author was a retired University of Paris professor (thus Jehan des Murs’s senior colleague) who had
returned to his birthplace in Belgium to work on this grandiose project, which he intended as a summa
summarum—a universal compendium—of musical knowledge. The young innovators of the “Ars Nova,”
by extending the boundaries of musical theory, threatened the completeness of Jacobus’s account, so he
tried to discredit their advance and thus neutralize the threat.
The basic ploy was to dismiss the Ars Nova innovations as so much superfluous complexity, and to
show that their art, by admitting so much “imperfection,” was thereby itself made imperfect when
compared with what Jacobus called the “Ars Antiqua,” represented at its unsurpassable zenith by Franco
of Cologne. The term Ars Antiqua has also entered the conventional vocabulary of music history to denote
Parisian music of the thirteenth century; it is a bad usage, though, since the term has meaning only in
connection with its antithesis, and using it tends to ratify the notion that not just technique but art itself
makes progress.
Citing a passage in Jehan des Murs’s treatise in which the author explained the use of the term
“perfection” in music by saying that “all perfection does in fact lie in the ternary number” (beginning with
the perfection of God Himself, who is single in substance but a Trinity of persons), Jacobus maintained