Written texts are both abstract and physical objects: ideas, signs and shapes, whose meanings, graphical systems and social connotations evolve through time. To study this dual nature of texts, paleographers need to analyse large scale corpora at the finest granularity, such as character shape. This goal can only be reached through an automatic segmentation process. In this paper, we present a method, based on Handwritten Text Recognition, to automatically align images of digitized manuscripts with texts from scholarly editions, at the levels of page, column, line, word, and character. It has been successfully applied to two datasets of medieval manuscripts, which are now almost fully segmented at character level. The quality of the word and character segmentations are evaluated and further paleographical analysis are presented.