This study first examines the marginal repertoire in two well-known manuscripts, the Psalter of Guy de Dampierre and an Arthurian Romance, within their material and codicological contexts. This repertoire then provides a template for an extended study of the marginal motifs that appear in eighteen related manuscripts, which range from a Bible to illustrated versions of the encyclopedias of Vincent de Beauvais and Brunetto Latini. Considering the manuscript as a whole work of art, the marginalia’s physical relationship to nearby texts and images can shed light on the reception of these illuminated books by their medieval viewers.