Abstract

This chapter examines various thirteenth-century chronicles to assess their reactions to Pope Gregory IX's efforts in the field of the persecution of clandestine heretics. The central focus is Gregory's creation of the new role model of the plenipotentiary inquisitor, an innovation tested in the persecution campaigns of the Dominican Friar Robert le Bougre in northern France and Champagne and of the priest Conrad of Marburg in Germany. Among those analyzed which concern Conrad are the chronicle of Alberic of Troisfontaines, that of the Dominicans of Erfurt, the Annals of Worms, and the Deeds of the archbishops of Trier, while the works of Philippe Mousket, Matthew Paris and Richer of Senones concern Robert. They are examined not just as sources of information but with regard to their contexts and discussed in terms of their treatment of the inquisition.

Keywords: Heresy, inquisition, chronicles, Conrad of Marburg, Robert le Bougre

This chapter deals with the innovation and intensification which Gregory IX brought to the persecution of clandestine heretics – especially when he tested a new model, the plenipotentiary inquisitor, provided with a newly adapted set of rules for legal procedures – and with the impact these developments made on contemporary chroniclers. More precisely, it will contrast the slight impression which the pope's measures against heretics in Rome and Northern Italy left in the historiography with the deep imprint left by the actions of his most famous inquisitors: the Dominican friar, Robert le Bougre, who acted as malleus haereticorum in Northern France and Champagne in 1232/1233 and again in 1236 to 1239, and then disappeared, perhaps into monastic confinement; the notorious priest, Conrad of Marburg, who unleashed a wide-ranging persecution of heretics in Germany from October 1231 until his assassination by some of his would-be victims in June 1233.

During Gregory's pontificate significant changes in the procedures against heretics took place. Canon law substituted the trial based on accusatio and defensio with the processus inquisitionis, the investigation ex officio. In consequence, specific forms of heresy trial were developed, in which the accused gradually lost rights which had been taken for granted in traditional law-suits.