The picture which is the subject of this paper is a canvas measuring 3 ft. 4½ in. in height and 2 ft. 8½ in. in width, now enclosed within a plain narrow gilt frame, which used until recently to hang behind the green baize door of the Bursary at New College, Oxford, and now is hung in the room there known as the Chequer. It was so completely blackened by time that some sixty years ago Warden Sewell attributed it to Richard Haydocke; but, as we shall see, Haydocke was the donor rather than the artist. Recently, even the words ‘Ric. Haydocke’ upon which the Warden had based his inference had become invisible, and indeed the only judgement that could safely be passed upon the canvas was that it was a painting. Some frequenters of the Bursary never even noticed its existence; but the more observant would, after one glance, abandon the attempt to solve its riddle. Nor would any attention have been paid to it, had it not been that, on the Bursary being redecorated, Mr. Albert Rutherston suggested that the picture might be cleaned, and so it has come about that the skill of Mr. B. Comfort of Woodstock has revealed a curious commemoration of the Gunpowder Plot, painted in 1630, the semijubilee of the conspiracy, by the hands, as would seem probable, of John Percivall of Salisbury.