In 1226, Peter de Dreux, duke of Brittany (1213-37), ordered William, the seneschal of Rennes, to conduct an inquest into the knight-service owed by the bishop of Dol to the duke.2 William began his enquiries informally. Having been told by a number of people that John Paynel, Alan de Beaufort and Peter du Guesclin owed knight-service to the bishop, William summoned the three to Rennes to give testimony on the subject. All three refused to appear. When they persisted in this recalcitrance, the seneschal resorted to an alternative procedure, ‘that the truth of this matter should be enquired into by lawful testimony of the patria (legitimum testimonium patrie)’. This chapter will consider the testimonium patrie as a source for medieval memory and as one means by which contemporaries harnessed memory as a source of historical information.