 The Ratio Studiorum of the Jesuits made it incumbent on their professors of Scripture to acquire a mastery of Greek, Hebrew, and other Oriental languages.Alfonso Salmeron, one of the first companions of Ignatius Loyola, and the pope's theologian at the Council of Trent, was a distinguished Hebrew scholar and voluminous commentator.Bellarmine, one of the first Christians to write a Hebrew grammar, composed a valuable commentary on the Psalms, giving an exposition of the Hebrew, Septuagint, and Vulgate texts.