Above: Diagram of the celestial climate zones; Below: Diagram of the terrestrial climate zones — "Following ancient writers, medieval scholars identified five climactic zones: the Arctic and Antarctic, or North and South frigid zones; the North and South temperate zones, extending from the Tropic of Cancer to the Arctic Circle and the Tropic of Capricorn to the Antarctic Circle; and the torrid zone between the two tropics. Only the temperate zones were thought to be habitable. In the upper diagram, the five climate zones are shown in an abstract configuration resembling a flower with five circular petals. In his De natura rerum, Isidore of Seville (d. 636 CE) relates the zones to the five fingers of the human hand. As the hand was a fundamental mnemonic tool in the ancient and medieval worlds, Isidore’s likening of the petals to fingers makes this diagram an effective memory device. In the lower diagram, the zones are rendered as if projected onto the globe, as arcs and circles."

Featured on PDR in the collection Cosmography Manuscript (12th Century)

This wonderful series of medieval cosmographic diagrams and schemas are sourced from a late 12th-century manuscript created in England. Coming to only nine folios, the manuscript is essentially a scientific textbook for monks, bringing together cosmographical knowledge from a range of early Christian writers such as Bede and Isodere, who themselves based their ideas on such classical sources as Pliny the Elder, though adapting them for their new Christian context. As for the intriguing diagrams themselves, The Walters Art Museum, which holds the manuscript and offers up excellent commentary on its contents, provides the following description: