It is well known the Society of Jesus was involved in the teaching and practice of mathematics and astronomy in the 16th, 17th and 18th centuries in Europe and East Asia. In Portugal, from 1540 to 1759, the Jesuits developed and maintained a vast network of colleges and were responsible for the education of around 20 000 pre-university students. With the expulsion of the Order by the Marquis de Pombal (1759), the Jesuit colleges were closed and the educational system was shattered. The secularization of the educational system was accompanied by a massive political campaign in which the Jesuits were considered the major obstacle to scientific progress. This accusation of obscurantism and scientific illiteracy was largely accepted in Portugal in the 18th century and persisted throughout the 19th century. When the Jesuits returned to Portugal (1848), in order to recover its scientific and social credibility, they made scientific research a priority. Among their initiatives, they established “Brotéria”, a scientific journal with original research papers. Founded in 1902 by three teachers of the Jesuit college of São Fiel (Castelo Branco, Portugal), it published 400 popularization articles and more than 1300 research papers on zoology, botany, biochemistry and molecular genetics. It is one of the most significant learned and scientific journals in Portugal in the 20th century. By analyzing Brotéria’s publications (1902-2002), I plan to shed some light into the outer tensions and the inner desires that led a religious order to deeply engage in scientific practices in order to recover its social credibility.