Jean-François Nieus, F.R.S-FNRS research fellow at UNamur for nearly 20 years, readily describes himself as a "document hunter." Fascinated by the mysteries of the Middle Ages, he explores a period still marked by gray areas and clichés. His main field of study? The documentary practices of the aristocracy of northern France and the former southern Netherlands, which shed light on the political, social, and cultural mechanisms at work between the 11th and 13th centuries.