Medieval Diagram

Length of Seasons: The description in the text and the diagrams in the manuscripts coincide well. The purpose of the diagram is solely to show that the four equal quadrants of the zodiac contain four unequal lengths of the year and what those lengths are. Initially the circle of the twelve signs is laid out, usually within a circular band, sometimes on the outside of a single circle. The four cardinal points ABΓΔ are set anti-clockwise at 90-degree intervals, beginning with A at Aries 0° and at 12 o'clock. Two perpendicular diameters connect the pairs of points AΓ and BΔ. The letter Θ appears at the centerpoint, where the diameters intersect.