JANSSEN, yans'sen, JOHANNES: Roman Catholic; b. at Xanten (15 m. a.e. of Cleves) Apr. 10, 1829; d. at Frankfort Dec. 24, 1891. He studied at Münster, Louvain, Bonn, and Berlin from 1849 to 1853 (Ph.D., Bonn, 1853), and was professor of history in the gymnasium of Frankfort from 1854 until his death. He was ordained to the priesthood in 1860, was a member of the Prussian House of Deputies in 1875-76, was created a domestic prelate to the pope and an apostolic prothonotary in 1880. His theological position was so ultramontanistic as to evoke sharp criticism from Protestant historians for his partizan views of the moral, economic, and religious results of the Reformation. Of his many books the chief is the monumental Geschichte des deutschen Volkes seit dem Ausgang des Mittelalters (8 vols., Freiburg, 1879-94), the last three edited and completed by L. Pastor; Eng. transl. by M. A. Mitchell and A. M. Christie, Hist. of the German People at the Close of the Middle Ages, 12 vols., London, 1896-1907; Pastor has also reedited the whole work, and has supervised the publication of a series of monographs in defense of it under the title Erläuterungen und Ergänzungen zu Janssens Geschichte des deutschen Volkes (6 vols., Freiburg, 1898-1908). Janssen replied to his critics in his An meine Kritiker (Freiburg, 1882) and Ein zweites Wort an meine Kritiker (1883).

BIBLIOGRAPHY: L. Pastor, Johannes Janssen, 1829-91, ein Lebensbild, Freiburg, 1893; F. Meister, Erinnerung an Johann Janssen, Frankfort, 1896.

JANNSENS, ERASMUS (ERASMUS JOHANNES) Dutch Unitarian theologian; b. about 1540; d. at Clausenburg (220 m. e.s.e of Budapest) 1596. He became rector of the college at Antwerp in 1576, but because of his Socinian teaching was compelled by William of Orange to resign and go into exile. He became rector of the college at Emden, and in 1579 he went to Frankfort, where there seemed prospects of larger religious liberty. But his Clara demonstratio Antichristum immediate post mortem apostolorum coepissi regnare in ecelesia Christi (n.p., 1584) caused him new trouble, and he emigrated to Cracow in Poland. A disputation with Faustus Socinus Nov. 29-30, 1584, led to Janssens' De unigeniti filii Dei existentia (Cracow, 1595). A little later Janssens withdrew his opposition to the Unitarian doctrine, being offered the pastorate of the Unitarian church at Clausenburg, in the service of which he closed his life.

His system of theology is stated in his Antithesis doctrinæ Christi et Antichristi de uno vero Deo (n.p.,1583; reprinted with refutation by J. Zanchius, Neustadt, 1586). He was author also of Scriptum quo causas propter quas vita æterna contingat complectitur (1589), and furnished the part on the prophets in the Latin Bible of Tremellius and Junius (Frankfort, 1579).

BIBLIOGRAPHY: C. Sandius, Bibliotheca antitrinitariorum, passim, Freistadt, 1684; J. N. Paquot, Mémoires pour servir à l'hist. littéraire de . . . Pays-Bas, vii. 328-333, 18 vols., Louvain, 1763-70; J. C. A. Hoefer, Nouvelle biographie générale, xxvi. 357, Paris, 1861.