For six centuries the book-trade of Paris and of France, whether it consisted in the production of manuscripts for the exclusive use of members of the university, or of printed books for the enlightenment of the general public, had been obliged to do its work under the hampering and burdensome regulations and restrictions of a varying series of authorities. The rectors of the university, the theologians of the Sorbonne, the lawyers of the Parliament of Paris, the chancellors of the Crown, the kings themselves, had all taken a hand, sometimes in turn, not infrequently in conflict with each other, in the task of “regulating” the trade in books. The burden of the restrictions was, in pretence at least, offset by various privileges and exemptions, but they remained burdens notwithstanding. It may well be a cause of surprise that in the face of such a long series of hampering difficulties, difficulties more serious than those with which any publishers in the world, outside of Rome, had to contend, the manuscript publishers and the later printer-publishers of Paris should have been able to do so much to make Paris a literary and a publishing centre. As has been already indicated, it was certainly the case that during the thirteenth and fourteenth centuries Paris shared with Florence the position of being the centre of the manuscript trade of Europe. It was also the case, as will be set forth in a later chapter, that the first printer-publishers of Paris did most noteworthy work in furthering the development of scholarly publishing and the production of scholarly books. It required, however, the revolution of 1789 to establish the principle that the business of producing and distributing books could secure its legitimate development only when freed from censorship restrictions and regulations, and that it was a business the control of which belonged properly not to the university, the Courts of Parliament, or the Crown, but to the people themselves. Considering the scarcity and the costliness of books in the Middle Ages, it is somewhat surprising that the work of instruction rested so directly upon books, that is, depended upon the mastery of a text. Thurot says: “It is the distinctive character of instruction in the Middle Ages that the science was not taught directly and in itself, but by the explanation of books which derived their authority solely from their writers.”[299] Roger Bacon formulates it: “When one knows the text, one knows all that concerns the science which is the object of the text.”[300] Instead of taking a course of logic or of ethics, says Compayré, the phrase was reading a book on logic or ethics, _legere_ or _audire librum_. This close adherence to the text secured, of course, an assured demand in the university towns first for the hired _pecias_ and later for the purchased manuscripts.