Astronomical and cosmological diagrams of the Latin Middle Ages deal with the visual perception of the world, illustrate the movements of the planets and explain celestial phenomena. They are often based on visual experience, but also surpass the sensual perception of the world and locate what one sees within a tested order. Kathrin Müller shows that diagrams played a key role in the semantization of the world in the Middle Ages. Diagrams not only record and convey knowledge, but also make statements about the knowledge of the world presented. In the transition from the High and Late Middle Ages, the forms of diagrams changed, and diagrams now increasingly mediated between book learning and the sensual exploration of the world.