JAHN, Johann, a German orientalist, born at Taswitz, Moravia, June 18, 1750, died in Vienna, Aug. 16, 1816. From his youth he was devoted to the study of the eastern languages. Having removed to Vienna, he was appointed professor of dogmatic theology and of oriental literature in the imperial university; but in 1806 he was compelled to resign on account of his heterodox opinions, and was appointed canon of the metropolitan church of St. Stephen. He was the author of various philological and theological works, the most important of which are his Chaldean, Arabic, Syrian, and Hebrew grammars; his Introductio in Libros Sacros Veteris Testamenti (1804; 3d ed., 1825; translated into English by Drs. Turner and Whittingham, New York, 1827); and his Biblische Archäologie (2 vols., 1797-1800; translated by Prof. Upham, Andover, 1839).