WHEN Jean-Jacques Rousseau claimed (in his Dictionnaire de musique, 1768) that “a baroque music is that in which the harmony is confused, charged with modulations and dissonances, the melody is harsh and little natural, the intonation difficult, and the movement constrained,” he was writing from the rather smug viewpoint of the French Enlightenment. Here “baroque” is used in an early sense of extravagant, bizarre, even “gothic.” The broader notion of the Baroque as a distinct style-period from the mid or late sixteenth century to the early or mid eighteenth century gained ground instead in the nineteenth century, particularly in art history by way of Jacob Burckhardt, Heinrich Wolfflin, and Willibald Gurlitt. Wolfflin later expanded his argument to embrace a range of stylistic alternatives distinguishing the Baroque from the Renaissance (painterly rather than linear styles, open rather than closed forms, etc.) and also reflecting broad pendular motions within the Western tradition. Various attempts to apply these categories to music have been brave but controversial—comparisons between music and painting always founder on the rock of metaphor—but the force of (and clearly visible evidence for) notions of the Baroque in art history established terms that (as Wolfflin himself suggested) literary and music historians could scarcely ignore, even if the detail might be different in their own fields.

The search for common factors underpinning the arts of a given period tends to focus either on ill-defined but seductive notions of a “spirit of the times” or on a more precise articulation of contextual perspectives. Robert Haas's Die Musik des Barocks (1928), the relevant chapters of Paul Henry Lang's Music in Western Civilization (1941), and Friedrich Blume's entries on “Renaissance” and “Barock” for Die Musik in Geschichte und Gegenwart variously followed the trend for music. A more autonomous stance was adopted by Manfred Bukofzer in Music in the Baroque Era : From Monteverdi to Bach (1947)—focussing on the music's inner stylistic unity—Suzanne Clercx's Le Baroque et la musique (1948), and Claude Palisca's Baroque Music (1968) : here “Baroque” runs the danger of being treated more as just a label of convenience.