As a master of the sacred page (manuscripts of theology in Latin), Grosseteste trained the Franciscans in the standard curriculum of university theology. The Franciscan Roger Bacon was his most famous disciple, and acquired an interest in the scientific method from him. Grosseteste lectured on the Psalter, the Pauline epistles, Genesis (at least the creation account), and possibly on Isaiah, Daniel and Sirach. He also led disputations on such subjects as the theological nature of truth and the efficacy of the Mosaic Law. Grosseteste also preached at the university and appears to have been called to preach within the diocese as well. He collected some of those sermons, along with some short notes and reflections, not long after he left Oxford; this is now known as his Dicta. His theological writings reveal a continual interest in the natural world as a major resource for theological reflection and an ability to read Greek sources (if he ever learned Hebrew, it would be not until he became bishop of Lincoln). His theological index (tabula distinctionum) reveals the breadth of his learning and his desire to communicate it in a systematic manner. However, Grosseteste's own style was far more unstructured than many of his scholastic contemporaries, and his writings reverberate with his own personal views and outlooks.