Modal Theory, Church Keys, and the Sonata at the End of the Seventeenth Century

Abstract

In the latter half of the seventeenth century, two composers, Giovanni Maria Bononcini and Giulio Cesare Arresti, published collections of sonatas arranged according to modal criteria. Although their conceptions of a modal system differ markedly from one another and from other modal theories of the period, Bononcini's and Arresti's common use of a particular set of eight tonalities concurs with a widespread practice among seicento sonata composers that was also widely attested by theorists. In their music, composers extended these eight tonalities to greater numbers through transpositions. This practice thus reflects an a priori conception of a tonal system based on a core set of tonalities plus transpositions of that set. This core set derives, not from the modes, but from tonalities originating in the eight psalm tones used in the Catholic offices. The significance of these psalm tone tonalities-otherwise known as church keys-cannot be underestimated: they provide a crucial link between seventeenth-century modal theory and the musical practice of that period; moreover, the particular characteristics of the psalm tones themselves explain features found in late seicento tonalities.