Scholars of pre-modern legal history face interesting problems with the interpretation of their materials because the ideal of fixed written laws is compromised by the variability in handwritten transcription of the texts. The variability may lead to inadvertently peculiar readings of the law in specific instances, or may have resulted from deliberate manipulation of the texts to adapt them to particular interests or circumstances. While such textual evolution occurs in many professional fields (medicine, music, liturgy, etc.), it raises especially interesting questions in the field of legal studies because of the implications for the authority of the text and the threshold of “forgery.” This paper investigates new methods for assessing the relationship between “standard” versions of legal texts and the degree and frequency of alteration in manuscript witnesses, using the Carolingian Canon Law project as one possible model for using a digital environment to study the histories of “living texts”, that is, texts that potentially mutate in each manuscript representation.