In the 13th-century, western Europe rediscovered Aristotle's books on natural philosophy, or natural science ('Libri naturales'), and this caused an intellectual revolution. Despite being banned in Paris early in the century, they quickly became part of the curricula of universities. Oxford, where this manuscript was probably made, was a leading centre for the study of Aristotle. All students had to read set texts of Aristotle's treatises with commentary, of which this book is an example. It is exceptional, though, because it is quite richly decorated with unusual images. Furthermore, it belonged to Nicholas of Cusa, a German theologian and cardinal, in the 15th century. The first section of the 'Natural Philosophy' textbook is 'Physics' ('Physicorum'). Why is the first letter decorated with a scene of book-burning? A king and a crowd, including a Franciscan friar, look on while a boy throws books down onto a fire. It has been suggested that because no earlier copies of the book had extensive decoration and the text itself is highly abstract, contemporary events surrounding Aristotle's natural science books provided the inspiration for the manuscript's unusual pictures. Some authorities still disapproved of them, and the Franciscans were the most active promoters and teachers of Aristotle's natural philosophy. Or it could refer to some incident in the life of Aristotle, who was tutor to King Alexander the Great. The pair of battling statues above the picture and the sleeping figure below are just as difficult to explain. Nonetheless, the elaborate decoration must have provided entertainment during study breaks.