Cette thèse, motivée par les recherches récentes sur la « rhétorique musicale », étudie le nombre éloquent, notion aux nombreuses ramifications dans les domaines oratoire et poétique, encore peu examinée dans le champ musical. L’approche est philologique, comparatiste et historique, et vise à déterminer dans quelle mesure, entre 1600 et 1750, les modes d’approche et de perception du nombre en poésie et dans l’art oratoire ont eu leur équivalent en musique, en Italie (jésuite essentiellement) et en Allemagne. Après une mise en perspective de la culture des spécialistes de musique, partagée entre rhétorique scolaire et éloquence adulte, l’examen du découpage conceptuel opéré par les Anciens entre oratio vincta et soluta permet d’identifier des modes de composition, d’écoute et de prononciation du discours musical vocal et instrumental. La perception de la stricte récurrence propre à la musique métrique (vincta) contraste avec celle de la bigarrure variée de la musique « en prose » (soluta), et les approches érudites et néophytes diffèrent. Au plan micro-structurel, les périodes musicales sont abordées à l’instar des périodes oratoires. Selon qu’elles sont « arrondies » ou « articulées », elles mettent en œuvre le nombre grâce aux rythmes, à la conduite harmonieuse et à un travail de structuration par amplification. L’écriture périodique apparaît comme un principe fondamental de composition. La réflexion sur l’éloquence du nombre en musique s’inscrit finalement dans le débat touchant le meilleur style. Tenants de la brièveté musicale et partisans de l’abondance s’opposent, appliquant au domaine musical les réflexions sur le laconisme, l’atticisme et l’enflure. / This dissertation was undertaken in the wake of the recent research about musical rhetoric and focuses on the rhetorical number, a concept of acknowledged significance in the field of oratory and poetry that as yet has seldom been examined in the field of music. Following a philological, comparative and historical approach, the present study aims at determining to what extent the modes of perception and approach of the numerus in poetry and rhetoric had counterparts in music in Italy (mainly among the Jesuits) and Germany between 1600 and 1750. The study first deals with the culture of music specialists, which relates partly to scholastic rhetoric and partly to mature eloquence, and then investigates the conceptual division set by the Ancients between oratio vincta and soluta, so as to show that such division makes it possible to delineate the composition and listening and pronunciation processes of musical discourse, both vocal and instrumental. Perception of the strict recurrence that is specific to metrical music (vincta) contrasts with the heterogeneous variety of « prose »music (soluta) and it differs among scholars and novices. As for the microstructures of discourse, musical periods are tackled similarly to oratorical periods. Whether they are « rounded » or « articulated », they become rhythmical thanks to metrical feet or harmonious structure as well as processes of amplification. Periodical style appears fundamental to composition. The present dissertation eventually shows that the discussion of musical oratio numerosa is related to the impassioned debate over the best musical style (brevity, abundance, laconism, atticism and bombast).

The keyboard toccatas of J. S. Bach, BWV 910-916, present a formidable challenge of interpretation to the modern-day performer. These works contain some of the most unusual compositional techniques to be found in Bach’s output due to their use of an improvisatory, virtuosic style inherited from the seventeenth century. While pianists of today are trained to perform with perfect fidelity to the score, the treatises from the time of Bach point to a rhythmically free approach to the improvisatory features of these toccatas. The goal of this treatise is to explore how the historical tradition from which Bach’s toccatas emerged influenced their stylistic characteristics with the purpose of applying this information to create an informed performance by today’s interpreters. In this effort, this treatise focuses on several broad categories in the process of understanding the inspiration and, therefore, the interpretation of these works. These categories include the genesis of the toccata as a genre, the compositional techniques associated with the toccata, Bach's personal contribution to the genre, and the interpretation of Bach's toccatas specifically. / text