This thesis investigates the role of the peregrinus psalm-tone in the liturgies of the Western Church up to c.1750. Its apparent function as a recitation formula on par with the eight regular tones, as implied in the earliest sources, is taken as a starting point for an investigation of its gradual marginalisation in Western psalmody.
Several theories of the origin of the tonus peregrinus are analysed in detail. Being a remnant from a Middle-Eastern or Greek tradition, the psalm-tone acquired important fixed functions in liturgies of Roman Catholicism (with Ps. CXIII, In exitu Israel), Lutheranism (with the Magnificat; Meine Seele erhebt den Herren) and in the Anglican Church (with several New-Testament Canticles). As a result of this, it has served as a basis for a multitude of polyphonic settings over a period of more than five hundred years. The diverse styles and idioms in which it has been incorporated and the extent to which it has given rise to modification of existing formulŠ on account of its unique features is discussed throughout a chronological canon of important tonus peregrinus settings.
A historiography of the psalm-tone is followed by a chapter on the concept of peregrinatio in mediaeval theology. The main corpus of the thesis is the above-mentioned analysis of polyphonic settings, separated into chapters of: liturgies before 1500; sixteenth-century Iberian Catholicism; sixteenth-century Apennine Catholicism; sixteenth-century Franco-Flemish Catholicism; Northern-European Catholicism of the sixteenth century; sixteenth-century Lutheranism; sixteenth-century Anglicanism; Roman-Catholicism c.1600-c.1750; Lutheranism c.1600- c.1750. The thesis also includes a chapter in which the tonus peregrinus is discussed in relation to the aeolian modus in the modal systems of Glareanus and Zarlino.