Text segmentation is an important prerequisite for document navigation and structure understanding. Previous works have been mainly concerned with narrative, expository or user dialogue texts, under the strong hypothesis of topical shifts to perform text segmentation. In this paper, we address books of hours, Latin devotional manuscripts of the late Middle Ages that exhibit challenging issues: a complex hierarchical entangled structure, variable content, noisy transcriptions with no sentence markers, and strong correlations between sections for which topical information is no longer sufficient to draw segmentation boundaries. We show that the main state-of-the-art segmentation methods are either inefficient or inapplicable for books of hours and propose a bottom-up greedy segmentation approach that achieves significant results.