In the modern world, we don’t assume that sermons and book prologues should be done in the same style, or that book prologues and introductory lectures should share the same style, let alone that either of these should be written as sermons. Yet the sermo modernus style we have just described was used in all three types of principia distinguished in Chapter 2: introductory lectures, book prologues, and inception addresses. What order of development resulted in all three making use of the same style is unknown to us. Whether masters first developed a new method of introducing students to a book that would help them keep its sections in memory and then later found it useful for sermons, or whether a style of preaching was incorporated into the methodology of the classroom, we do not know. What we do know is that by the time Thomas and Bonaventure incepted as masters at Paris in 1256 and 1254 respectively, the sermo modernus style was accepted as the default mode for delivering principia of any type, written or oral, and no one seems to have questioned the practice.