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 set textbook includes Aristotle's treatise on weather ('Meteorologica'). Each section has a decorated first letter, some with pictures (historiated initial). Section Four's historiated initial is famous because it has one of the earliest surviving depictions of a post-windmill, a recently introduced technological advance. The man beside the windmill guides its tailpole. It is a new way of depicting the winds, which earlier were usually depicted by human heads blowing with puffed-cheeks, positioned at the four cardinal points around a circular image of the world (a 'wind-rose'). The pictures in this natural science textbook inventively use images from a variety of types of book illustration and contemporary life.