This article examines the revision of liturgical chant manuscripts at a single Premonstratensian house in the Low Countries, with focus on a period of religious upheaval in the seventeenth century. Sint-Catharinadal, founded in Vroenhout in 1271 for a community of sisters, had a difficult history. Between its founding and the seventeenth century, the house relocated more than once: first to Breda, and then to its present location in Oosterhout. During this period, its chant books also underwent substantial revision. Its surviving manuscript sources that contain music for the Divine Office show textual and notational changes that coincide with later publications of the Premonstratensian antiphoner; however, unlike manuscripts from other houses, these revisions are partial and at times inconsistent. Taking stock of the surviving collection of sources preserved at Sint-Catharinadal, this article charts the process of revising older chant sources. This process was gradual, complicated and at times non-linear. Scribes often adopted individual approaches when revising their chants, including the use of notational systems commonly used for other repertoires, such as secular or keyboard music. What emerges is a location-specific and context-dependent picture of chant sources, where scribes exercised individual autonomy in the revision of repertoires, despite the calls for conformity and consistency that defined the early modern period.