This communication looks to continue a discussion initiated at the XVI Patristics Conference of the *Liber Genealogus*, an anonymous compilation from early fifth-century North Africa (see J.-B. Piggin, 'The Great Stemma: A Late Antique Diagrammatic Chronicle of Pre-Christian Time', StPatr 62 (2013), 259-78). Attention to this text has come largely from historians of genealogy; thus Piggin's goal in 2011 was to use the *Liber* to reconstruct the history of family trees as a visual means of representing kinship and lines of descent. Further, the influence of the *Liber* in resolving the problem of Mary's Davidic descent has long been acknowledged. My communication will address the text in what seems to have been the context of its production, namely Donatist North Africa. I will suggest that the interest of the text in tracing Mary's descent takes meaning from the vital and protracted discussion of lines of episcopal succession between Caecilianists and Donatists. Whether the *Liber* can also be related to new Christian understandings of marriage and the family is an open question.