As is well known to Ockham scholars, much of Ockham’s career as a teacher of theology in the years from ca. 1317-24 involved an ongoing debate with his confrère Walter Chatton. The latter’s commentary on the Sentences is conceived as a defence of his own interpretation of Duns Scotus, from which standpoint Chatton undertakes what is virtually a point-by-point rebuttal of Ockham, with nearly equal attention to the views of Peter Aureol. What has not received much attention is the frequency with which a third scholar is Chatton’s target. This is the secular theologian, Richard Campsall, who often appears in the commentary as an unnamed quidam, and who was probably the most impressive philosopher at Oxford in the years just before Ockham began his lectures on the Sentences. Campsall’s name is nearly forgotten today; indeed, as far as it is possible to judge on the basis of our relatively meagre knowledge of late fourteenth-century thought, before the end of the century Campsall’s fame had faded, and most of his important insights were already being assigned to others—chiefly to Ockham.