The debate that began back in 1955 with the Ars Nova conference held at the Château de Wégimont continues. Back then, Nino Pirrotta saw Philippe de Vitry's ars nova effectively as an ars nova notandi, rules for a new style of notation. Leo Schrade felt that the term had no historical validity after around 1330, but that there was something in advanced motets of the Roman de Fauvel – not just the novelties of rhythm, but also the very conception of musical art – that went beyond issues of notation. Suzanne Clercx, for her part, wanted to preserve the term, enshrined in common usage, as a label for the music of the entire fourteenth century.Footnote ¹ Karen Desmond's impressive new book addresses all these points. Moving well beyond previous scholarship, she defines ars nova in a manner authorised by contemporary witnesses, signalling specific changes in notation that in turn allowed for new compositional possibilities that indeed do embody a new conception of musical time. The book redefines the problem and will stimulate scholars to rethink the issues. Beyond this, the book is a rich cornucopia of materials – far more than can be discussed in the space available here – that engage the history of science and philosophy as well as musicology and music theory.

In an effort to put modern assessments of stylistic developments on firmer ground, Desmond clarifies precisely what techniques the treatises describe, and how the doctrines in the various treatises are related. She carefully lays out stages of mensural theory in this period of transition, from Johannes de Muris's first formulation in the Notitia to the surviving remnants of Vitry's Ars vetus et nova, to evidence gleaned from Jacobus's attacks on the moderni.Footnote ² A revised view of the dates of the treatises is one of the many contributions of the book (pp. 27–34). In 1970, Ulrich Michels had assigned many of the relevant treatises to the early 1320s.Footnote ³ Desmond reinstates a date of c.1319 for the Notitia, based on the explicit in BNF lat. 7378A. She argues, moreover, that the associated nine Conclusiones constitute an independent work, which postdates the Notitia, and that the Compendium may postdate the Notitia by as many as ten years or more (pp. 27–31).Footnote ⁴ All this in turn affects the dating of Jacobus's Speculum musice, since he quotes not only from Muris's Notitia, but also from his Conclusiones and Compendium. If a very late date for the Compendium holds, the Speculum may have been completed in the 1330s.Footnote ⁵ The net result is that many of the theoretical writings dealing with the specifics of ars nova notation – except the Notitia – have now floated to later dates, and all this raises serious questions about the dating of motets that incorporate the ars nova traits discussed in these treatises, such as minim stems and rests, remote imperfection and syncopation. Desmond's conclusion is that it was not until around 1330 or later that the full notational accoutrements of the ars nova were available to composers.

Chapter 2, which concerns ‘subtilitas’, plays off a passage in the Tractatus figurarum (third quarter of the fourteenth century) that compares Tribum / Quoniam (a Fauvel motet usually attributed to Vitry) with Apta / Flos (a motet some also attribute to Vitry, albeit one composed at the end of his life). The former exhibits what might be termed an ‘artless simplicity’ (grosso modo), the latter a ‘more subtle art’ (ars magis subtiliter).Footnote ⁶ There is a lengthy analysis of each motet, very useful for Apta / Flos (Appendix 5 provides a new edition in diplomatic ars nova notation; the new translation by Joshua Benjamins of the difficult triplum text is welcome), but in my view off the mark for Tribum / Quoniam, inasmuch as it downplays its innovations and expressive force. The old historiography that distinguished two stages of development, an ars nova and an ars magis subtiliter (using the terms as labels of musical styles) remains defensible.Footnote ⁷ Desmond's historiography of both the positive and the negative connotations of subtilitas ranges too widely chronologically to convince me that Jacobus, in his condemnation of the subtilitates of the moderni, was thinking along the lines of the author of the Tractatus figurarum, and thus that Jacobus must have been referring to works as advanced as Apta / Flos. Jacobus's knowledge of syncopation is the crucial matter. Discussing semibreves, he states: ‘Certain [teachers] syncopated some of them, but figured others half-full inside.’Footnote ⁸ From this, the unique mention of syncopation in the entire Speculum, Desmond infers that ‘The moderns’ technique of syncopation was criticised by Jacobus’ (p. 61; see also pp. 68, 156, 158). It seems to me more likely that Jacobus is noting an oddly shaped semibreve, one with something missing from the middle, playing off the grammatical meaning of a syncope (e.g. where ‘forsan’ stands for ‘forsitan’); the ‘half-full’ figure is probably the signum rotundum, which Jacobus took for a semibreve.Footnote ⁹ It is also unlikely that Jacobus was referring to a work such as Apta / Flos when he lamented the ‘descent of these speculations into practice’ (p. 34), because that passage in Jacobus concerns combinations of perfect and imperfect modus and tempus, a compositional strategy dear to the early ars nova, but apparently passé by the time of Apta / Flos, which instead plays with syncopation in the lower voice as it holds to perfect maximodus, perfect modus, perfect tempus and major prolation.Footnote ¹⁰

The rest of the book alternates focus: Chapters 3 and 5 treat specific attributes of the personalities and philosophies of the theorists, whereas Chapters 4 and 6 treat details of notational theory and musical practice. Chapter 3 lays out the current state of knowledge regarding the biography of Johannes de Muris, going beyond music theory to consider Muris's important contributions to fourteenth-century astronomy and astrology, and incorporating current research from scholars of the history of science, mathematics and philosophy. Appendix 2 provides key dates in his life; Appendix 6 provides a valuable works list, separating Muris's many treatises into the categories music, mathematics and astronomy. The even distribution of tracts on astronomy and astrology throughout his career shows that these pursuits were his real passion, and that this side of his expertise was what attracted patrons at the university, at royal courts, as well as in the Church.Footnote ¹¹

Scholars of Muris's astronomical treatises have noted that his working procedure involved recasting and revising over many years, moving from initial pithy formulations towards practical accessibility, and Desmond finds this true of his music treatises as well. For example, Muris's concise treatment of ternary and binary divisions and their interaction along a temporal continuum in the Notitia underwent refinement and reworking: in the nine Conclusiones, by spelling out practical implications and addressing critics; in the Compendium, by adopting a user-friendly dialogue form. Finally, the Libellus cantus mensurabilis ‘secundum Johannis de Muris’, possibly a collaboration between Vitry and Muris, became the definitive vade mecum for ars nova notational theory.Footnote ¹²

Some of Jacobus's arguments against the moderni may seem silly from our point of view.Footnote ¹³ Desmond, however, shows in Chapter 5 that then-current philosophical controversies lie behind some of his arguments, such as those regarding imperfection. Upholding Aquinas's thesis of the unity of form and matter along lines argued by Godfrey of Fontaines, a native of Liège and master regent in theology at the University of Paris in the years 1285–99 and 1303–4, Jacobus maintained that a perfect long cannot be imperfected by a breve, because its form would be corrupted and destroyed, replaced by the form of an imperfect long (p. 180). Muris, possibly responding to Jacobus himself in the second and third Conclusio, argued that the essential form of a note is not imperfected, but a secondary form, namely its signification (p. 178).

The discussion of notation in Chapters 4 and 6 forms the core of the book. Chapter 4 focuses on the changing status of the semibreve in theory and practice. The aim is to show that the Fauvel motets do not exemplify ars nova notational techniques, because the notation of semibreves in Fauvel shows little advance on the post-Franconian principles associated with Petrus de Cruce. This strategy, however, preordains a negative conclusion. If one defines the notation of semibreve/minim values as a key element of the ars nova, then Fauvel motets will, ipso facto, never measure up. If, on the other hand, one focuses on a different problem, say, rationalising a system of ternary and binary values at different notational levels (duplex long, long and breve), leaving the semibreve aside for the moment, then advanced Fauvel motets emerge as interesting and important.Footnote ¹⁴ Further, this is the very aspect of Fauvel motets that shortly (perhaps before the completion of the Fauvel manuscript itself) found a rigorous theoretical exposition in the Notitia.

Desmond carefully evaluates treatises that witness the period before the full rationalisation of ars nova notational rules. CS3Anon3 defines the ars nova (‘which Philip de Vitry recently invented’) as the application of ars vetus rules for the imperfection and alteration of breves and longs to other degrees, breve/semibreve and semibreve/minim. Yet most of this treatise is devoted to a discussion of stock rhythmic patterns for resolving unsigned semibreves and diverse stemming practices that render imperfection and alteration moot at the minim-semibreve level. Desmond proposes that such formulas, found in other treatises as well, constitute a ‘guide for copyists’ busy transferring Fauvel-style notation into ars nova notation (p. 145). CS3Anon4 and CS3Anon2 consider Fauvel-style notation an ars vetus, while ars nova (‘in nova arte’ or ‘secundum novum modum notandi’) refers to an updated notation. Such evidence provides theoretical justification for Desmond's view that ars nova requires ‘fully theorised semibreves’ (pp. 141–7). Yet both of these treatises fall short of the comprehensive practical treatment found later in the Omni desideranti or Libellus. One begins to feel that ars nova was a moving target, not readily fixed to a given point in time.

A postdated ars nova also depends on when Jacobus was writing. Desmond summarises his state of knowledge: the moderni now mostly use up-stem minims, solitary semibreves imperfecting breves, imperfected duplex longs, four combinations of perfect and imperfect mensuration (perfectly perfect, perfectly imperfect, imperfectly perfect and imperfectly imperfect), syncopation and mensuration signs (pp. 156–8). If one were to omit syncopation from the list (as p. 147), which, as discussed above, I think was unknown to Jacobus in a rhythmic sense, he could have been writing a bit after 1325, after Tuba / In arboris, Se paöur / Diex, and Douce / Garison. If all this has to wait for the 1330s, as Desmond proposes, we would need to reckon with about fifteen years during which no new composition advanced the art beyond what we find in Fauvel. But I am suspicious of the notion that Jacobus's state of knowledge encompassed much modern practice, as opposed to written theory; even his famous outburst (‘Would that this speculation had not descended into practice!’) in its context – a discussion of the four combinations of perfect and imperfect modus and tempus – was probably prompted by written theory, since Vitriacan treatises list practical works, that is, specific motets, to illustrate these combinations.Footnote ¹⁵

Chapter 6 focuses on the use of notational dots of perfection and division to effect conflicting mensurations in different voices of a motet. An example is Vitry's Colla / Bona, with its triplum in imperfect modus and motetus in perfect modus throughout. Isolated dots can also bring about conflicting mensurations within a voice, as in Garrit / In nova. In her excellent analyses of Vitry's Vos / Gratissima, O canenda / Rex quem and Machaut's Hareu / Helas, Desmond shows that these works exhibit a new conception of temporality, ‘with single voices shifted along the line of time by a single temporal unit’ (p. 235). Yet several works that in Chapter 6 exhibit ars nova characteristics are works that were excluded from the ars nova in Chapter 4 because they were not conceived in mature ars nova notation.Footnote ¹⁶

In sum, Desmond has brilliantly teased out many strands relating to this multivalent term and has suggested many avenues for further research. It is, to be sure, impossible to pinpoint a single moment of ars nova. At each step along the way so much is new, and it seems that by the time we can confidently use the term, new compositional concerns have completely overtaken earlier stages (as with Tribum / Quoniam and Apta / Flos, each new in its time). This highlights the threefold ambiguity of the term evident at the 1955 Colloque de Wégimont, and the problem actually goes all the way back to the fourteenth century. The notion of an ars nova as opposed to an ars vetus, of moderni against antiqui, served various ends during the heated period of transition. For Jacobus, the old art encompassed Franco and Petrus, in its notation eschewing stemmed semibreves, but in its musical style an art of perfection, couched exclusively in perfect modus and tempus. Not only did the moderni offend the notational norms of the antiqui, but they also offended the foundations of musical style, mixing perfect with offensive imperfect relationships in a fashion that simply could not be reconciled with the old style. For some later theorists, style was irrelevant, and they limit their discussions to teaching the nuts and bolts of a new notation. Thus works that for Jacobus were impertinently modern in stylistic conception (e.g. the advanced motets of Fauvel) were ancient for some theorists as regards notation, representatives of an ars vetus. Although ars nova remains ambiguous, Desmond shows with unprecedented detail and precision that much can be gained by focusing on ars nova as a notationally defined phenomenon, broadening our knowledge of the achievements of Philippe de Vitry and Johannes de Muris.