Information on differentia
In the original Cantus index, differentiae were categorized according to their modal type (protus, deuterus, etc.), rather than their specific mode, based on the range of their accompanying antiphons. However, each differentia can be ascribed a specific mode, as shown here. The differentiae are mostly written as part of the main layout of the manuscript, with a few written in the margins. Some of the differentiae in this manuscript are written before the start of the antiphon that they accompany, rather than after the antiphon.
Zhang, Nan, Jennifer Bain, and Alessandra Ignesti. Inventory of Wiesbaden, Hochschul- und Landesbibliothek RheinMain, 2 (Riesencodex). Edited by Alessandra Ignesti, Barbara Swanson, and Clare Neil. In: Cantus Manuscript Database for Latin Ecclesiastical Chant: Inventories of Chant Sources. Directed by Debra Lacoste (2011-), Terence Bailey (1997-2010), and Ruth Steiner (1987-1996). Web developer, Jan Kolácek (2011-).
Images: [Hildegard von Bingen] (1180), online edition ([Wiesbaden] : [Hochschul- und Landesbibliothek RheinMain], )