While the Renaissance is most noted for its beautiful works of art, this period also introduced a more homely invention that soon reshaped the world—the printing press. Monks produced most books, painstakingly copying them by hand. The manuscripts they created were often very handsome, with painted decorations and illustrations, they were also very expensive, and so were used mainly by churches and by wealthy patrons among the nobility. With the rise of universities in the twelfth and thirteenth centuries, there was a growing demand for textbooks, Stationers in university towns kept a stock of these, which they copied themselves or lent to students for copying. A library of a hundred books was considered large, and the volumes were chained to shelves because of their value.