Confessor of Saint Elizabeth of Thuringia and papal inquisitor, b. at or near Marburg, Germany, in the second half of the twelfth century; d. 30 July, 1233. His contemporaries called him Magister, a proof that he had finished the course of studies at some university, perhaps Paris or Bologna. According to the Thuringian court-chaplain Berthold, and Cæsarius of Heisterbach, he was probably a secular priest, therefore neither a Dominican, as Hausrath states, nor a Franciscan, as is asserted by Henke and others. Papal letters and contemporary chroniclers describe Conrad as a man of much ability, large theological learning, great eloquence, ardent zeal in defence of the purity of Catholic Faith, and a severe ascetic. They also agree as to the sternness of his character. He is first heard of as a vigorous preacher of the crusade proclaimed in 1213 by Innocent III. The death of Innocent and the consequent relaxation of interest in the crusade, did not dampen the ardour of Conrad, while, in addition, he was charged with various important commissions. Honorius III authorized him (1219) to adjust the differences of the convent of Nihenburg with the Duke of Saxony and the Count of Askanien. The abbot of Hayna, the provost of St. Stephen, Mainz, and Conrad were appointed in 1227 papal commissioners for the separation of Marburg from the parish of Oberweimar. The synod of Mainz (1225) had issued several decrees for the improvement of the clergy and Conrad was intrusted with their execution; he was also charged with the reform of certain convents, as Nordhausen. In 1232 he describes himself as visitator monasteriorum in Alemanniâ. In the course of these labours Conrad became acquainted with the Landgrave Ludwig of Thuringia and his wife, St. Elizabeth. The prince held Conrad in high esteem, and the latter exercised great influence at the Thuringian court, being authorized by Ludwig to appoint to all ecclesiastical offices in the gift of the landgrave. This power of appointing to ecclesiastical livings was confirmed (12 June, 1227) by Gregory IX (Mon. Germ. Hist.: Epistolæ Sæc XIII, ed. Rodenberg, I, 276, n. 361).

In 1225, after the recall of the Franciscan Rodeger, Conrad became the spiritual director and confessor of the pious landgravine. He treated her with the same severity that he used against himself, a procedure in accordance with her own wishes. At times, however, he checked her pious zeal and forbade excessive mortifications. Conrad has been often blamed, quite unjustly, for the direction, in keeping with the custom of the time, which he imparted to the soul of St. Elizabeth. After the death of St. Elizabeth on 19 November, 1231, Conrad was deputed, with the Archbishop of Mainz and the Abbot of Eberbach, to examine witnesses concerning her life and the miracles attributed to her intercession. He also wrote for the process of canonization a short life of St. Elizabeth. In his later years Conrad was very active in Germany as papal inquisitor. The heresies of the Catharists and the Waldenses were spreading throughout the land; to Catharism, in particular, was owing the fantastic sect of the Luciferians (see Michael, Geschichte des deutschen Volkes, II, 266). From the beginning fo the thirteenth century the German ecclesiastical authority, in union with the civil power, had proceedeed vigorously against all heresies. The conflict in which Conrad had so large a share was waged according to the medieval views of public right and welfare. The first process in which he took part was that directed against Heinrich Minnike, Provost of Goslar. In 1224 after a trial that lasted two years, Minnike was declared guilty of heresy, delivered to the secular arm, and perished at the stake. In the following years Conrad preached with great vigour against the heretics and was warmly praised and encouraged to greater zeal by Gregory IX in a letter of 1227. The Archbishops of Trier and of Mainz both wrote to the pope in 1231 in praise of the extraordinary activity of Conrad and reported his triumphs over several heretical leaders. Thereupon Pope Gregory conferred on Conrad (11 October, 1231) the extensive authority of papal inquisitor, the first such officer appointed in Germany. At the same time the pope released Conrad from the obligation of following the ordinary canonical procedure (te a cognitionibus causarum habere volumus excusatum) and authorized him to proceed resolutely against heretics as he throught best, but with due observance of the papal decrees on the subject.

In the exercise of this authority, even according to the sympathetic accounts of contemporary annalists, Conrad proved too severe and harsh. His assistants, Conrad Dorso, a Dominican lay brother, and John, a layman, were ignorant fanatics unqualified for such work. Conrad believed too easily the declarations of persons accused of heresy; on the strength of their statements, and without further investigation, others were arrested and treated as heretics. The accused either confessed their guilt and had their heads shaved for penance, or denied their guilt, were delivered as obstinate heretics to the secular arm, and perished at the stake. How great was the number of victims cannot now be ascertained. In western Germany a general panic followed the appearance of this severe judge of heretics, who did not fear to summon before his tribunal powerful nobles, suspected of heresy, among such the Count of Sayn. The count appealed to the Archbishop of Mainz who convened a synod of his suffragans (25 July, 1233), at which King Henry also assisted. Both the bishops and the influential nobles were generally ill-disposed towards Conrad, who was present at the synod, and it was found impossible to prove the charge of heresy against the Count of Sayn. Thereupon Conrad undertook, in the exercise of his papal commission, to preach a crusade against heretic nobles. Shortly afterwards (30 July, 1233) both he and his companion, the Franciscan Gerhard Lutzelkolb, were murdered while returning to Marburg. He was buried in Marburg near St. Elizabeth. Despite the unfavourable action of the synod of Mainz, Gregory IX extended his protection to the memory of the deceased inquisitor and insisted that severe punishment be meted out to his murderers.

HENKE,Konrad von Marburg, Beichtvater der hl. Elisabeth und Inquisitor (Marburg, 1861); HAUSRATH,Der Ketzermeister Konrad von Marburg, in Kleine Schriften (Leipzig, 1883), 137-233; BECK,Konrad von Marburg, Inquisitor in Deutschland (Breslau, 1871); KALTER,Konrad von Marburg und die Inquisition in Deutschland (Prague, 1882); MICHAEL,Gesch. das deutschen Volkes (Freiburg, 1899), II, 109, 206 sqq.; 318 sqq.; HUYSKENS,zum 700. Geburtstage der hl. Elisabeth von Thüringen, Studien über die Quell. ihrer Gesch. in Histor. Jahrb. (1907), XXVIII, 499 sqq., 729 sqq.

J.P. KIRSCH