My research took me to Brussels, Amiens, Louvain, and Bruges, where I searched for the only existing copy of a lost manuscript by the medieval theologian and philosopher Baldwin of Bossu. Clues from catalogue records indicated that his commentary on Peter Lombard’s Sentences, a crucial contribution to the history of the free will debate, disappeared in the late 17th century. Long hours in rare books archives yielded a clue that led to the discovery of Baldwin’s commentary (a fragment) scrawled into the margins of another book by Albert the Great, the famous Dominican scientist who taught Thomas Aquinas.
