In the final years of the fourteenth century, waves of persecution shattered German-speaking Waldensian communities, with the scale of inquisitions matching or even greater than the better-known trials in southern France. In the middle of the persecution was the influential and enigmatic figure of the Celestine provincial and inquisitor of heresy, Petrus Zwicker (d.after 1404). His surviving texts and inquisition protocols offer a fresh, intriguing...