GRETSER, JAKOB. - Jesuit theologian, b. at Markdorf (Baden) on 27 March 1562, d. at Ingolstadt on 28 January 1625. He entered the Society of Jesus at Landsberg, studied at the University of Ingolstadt, where later he taught philosophy (1589-92) and then scholastic and moral theology, succeeding his master Gregorio di Valencia. In the controversies with Protestants he confronted Junius, Wittaker, Hunnius, Dresser, Pappus, Reinack, against whom he wrote many works that confer upon him an important place in the controversy.
His major work is the defence of Bellarmine: *Controversiarum R. Bellarmini amplissima defensio* (Ingolstadt 1607-1609). Another fundamental work is *De Cruce Christi* (ibid. 1598-1605), a veritable mine of erudition. Also noteworthy are: *De iure et more prohibendi, expurgandi et abolendi libros haereticos et noxios* (ibid. 1603), composed in favour of the *Index expurgatorius*, published by Philip II and printed at Antwerp in 1571, which had aroused the strongest resentment among Protestant writers; *Dissertatio pro sacratissima Corporis Christi solemnitate et sacrosanctae Eucharistiae cultu* (ibid. 1612).
Gretser left in all 233 works on the most diverse questions, preserved in the unique edition edited by P. G. Kolb (17 vols., Regensburg 1734-42).