The microcosm-macrocosm analogy was very important in Renaissance thought. An extensive treatment of this complex of ideas and its manifestations in intellectual currents such as magic and the occult, philosophy of nature, morals, and ethics would amount to an exhaustive study of Renaissance thought as a whole, to such a degree was this notion the motor of the intellectual life of that period…. Leonardo as well often referred in his manuscripts to this ancient analogy when he was describing the human body…. For Renaissance artists, the Vitruvian passage about the proportions for the homo bene figuratus presented an occasion to think again about the analogy between macrocosm and microcosm and to use it in a search for the essence of art and beauty. God created the cosmos with perfect proportions and in perfect harmony and, therefore, in perfect beauty. Man, as a microcosm, is a reflection of the macrocosm. Divine proportions can therefore be discovered in the human body. When an artist wants to make something beautiful it must be modeled on divine proportions. The artist therefore will use the human body as the most accessible and measurable system of divine proportions. Vitruvius recorded this system in this treatise. Through Leonardo’s unmistakable use of the medieval pictorial tradition in the representation of the Vitruvius passage, notions about the microcosm were fed automatically, as it were, into the new proportion theory. Because of the use of the medieval scheme of the homo ad circulum and ad quadratum the coupling of Vitruvian proportion theory with medieval analogy between macrocosm and microcosm became immediately visible for Renaissance readers. This underlines the independent status and meaning of the visual representation of ideas and concepts.