he was appointed by the archbishop-elector Francis George von Schönborn as his auxiliary bishop, being consecrated at Mainz, in February 1749, under the title of bishop of Myriophiri in partibus. Upon Hontheim as auxiliary bishop and vicar-general fell the whole spiritual administration of the diocese; this work, in addition to that of pro-chancellor of the university, he carried on single-handed until 1778, when Jean-Marie Cuchot d'Herbain was appointed his coadjutor. On April 21, 1779, he resigned the deanery of St Simeon's on the ground of old age. He was a man of short stature, energetic, hard-working, pious, and generous. He died on September 2, 1790, at his château at Montquintin near Orval, an estate which he had purchased. He was buried at first in St Simeon's; but the church was ruined by the French during the revolutionary wars and never restored, and in 1803 the body of Hontheim was transferred to that of St Gervasius. Historian As a historian Hontheim's reputation rests on his contributions to the history of Trier. During the period of his activity as official at Coblenz he had found time to collect a vast mass of printed and manuscript material which he afterwards embodied in three works on the history of Trier. Of these the Historia Trevirensis diplomatica et pragmatica was published in 3 folio volumes in 1750, the Prodromus historiae Trevirensis in 2 volumes in 1757. Besides a history of Trier and its constitution, they give a large number of documents and references to published authorities. A third work, the Historiae scriptorum et monumentarum Trevirensis omptissima collectio, remains in manuscript in the city library of Trier. These books, the result of an enormous labor in collation and selection in very unfavorable circumstances, entitle Hontheim to the fame of a pioneer in modern historical methods. It is, however, as Febronius that Hontheim is best remembered. His 1763 treatise "On the State of the Church and the Legitimate Power of the Roman Pontiff" offered Europe the "foremost formulation of the arguments against papal absolutism in Germany". The author of the book was known at Rome almost as soon as it was published; but it was not till some years afterwards (1778) that he was called on to retract. Threatened with excommunication and faced by the prospect of his relations' loss of their offices, Hontheim, after much vacillation and correspondence, signed a submission which was accepted at Rome