The six illustrations (“rotarum”) are illuminated in red, yellow, and blue ink. They include a 12-month calendar, a depiction of the cosmos, and diagrams of the seasons and climate zones. In the cosmological diagram, the Earth– a flat circle labeled “Terra”--  is shown to be at the center of the universe, surrounded by the Sun, Moon, and various planets, which move around the earth in circular orbits of increasing size. In the seasonal diagram, a circle representing the year is divided into labeled sections by a series of overlapping arcs. 

The five climate zones are represented by five circles within the larger circle of the earth. The earth is oriented northeast and labeled with the cardinal directions.  The zones, labeled “first” to “fifth", begin in the north and continue clockwise around the world: the first and fifth zones are cold and uninhabitable, the second and fourth zones are habitable, and the third zone is hot and uninhabitable. These climate zones touch at the edges, but do not overlap. The space in the center of the diagram is left blank.

De natura rerum was created by Saint Isidore of Seville, an author from Visigothic Spain. Isidore is most famous for his Etymologies, an encyclopedia of knowledge from the ancient world. He is also known for popularizing the circular representation of the world that is shown in De natura rerum. Isidore dedicated De natura rerum to Sisebut, a Visigothic king who ruled from 612 to 620 and is thought to have commissioned the book from Isidore. A poem about astronomy composed by Sisebut is included at the end of the manuscript. (Clara Fields 2027)