The tonus peregrinus in theory and praxis : comparing evidences of late medieval theoretical treatises and chant books

The history of tonus peregrinus has been treated in literature in many different ways. Covering the early phase of the term "peregrinus" has given an opportunity to examine the archaic modalities within the Gregorian antiphon repertory. In the 9th-10th centuries, when terms and examples of the "neophytus tonus" or "parapteres" and "tonus novissimus" respectively were put down in writing, the practice of psalmody and the inclusion of the melodies into the system of Octoechos did not follow strictly fixed norms yet. The "differentia peregrina" emerged as a characteristic appellation – as a label of an extraordinary psalm cadence – in the south German music theoretical writings of the late Middle Ages. It rose unnoticed from the irregular ending of the 8th mode to the rank of an independent tone and there are hardly any treatises and tonaries in Central Europe in the 14th-15th-centuries, moreover, following the Middle Ages that would fail to discuss it. The study intends to show how the notations of this rare melody formula in theoretical writings supplement the data missing from practical chant books. The explanations and antiphon examples of the late treatises included to demonstrate this tone help to elucidate the rational interpretations and musical considerations which contributed to keeping the concept of tonus peregrinus alive. And last but not least, the antiphons cited are used to examine how the singing practice supported or took into consideration the theoretical systematization