The 'Dragmaticon Philosophiae', was a reissuing of William of Conches’s 'Philosophia Mundi' (c. 1125), for which he is best known. The 'Dragmaticon' survives in eighty meticulously copied manuscript versions that were circulated over the next 400 years before the work was first printed edition by Josiah Rihel in 1567, Strasbourg.

Following the common conventions of T-O maps of the world in early books of knowledge, such as 

’s 'Etymologies', this map depicts the habitable world as a circle with East ('Oriens') at the top, West ('Occidens') at bottom, South ('Septentrio') to the left and North ('Auster') on the right. The cross section of the 'T' is rendered east to west. In the upper left quadrant of the map, the Indus River ('Indicus Mare') is prominently marked. The labelling of 'Europa' that usually adorns T-O maps is here replaced with Spain ('Hispania'). The unlabelled continent south of Africa - here, to the right - suggests a possible cartographic lineage that traces back to by Spanish geographer, Beatus of Liébana (c.730-798). It references the 'quadripartite', or four-continents, and is based on Islamic sources. This theory may also originate from a cosmological treatise by Jewish-Persian scholar Masha’Allah ibn Athari (c. 740-815)

The diagram in the lower right corner of the bifolium shows the phases of the moon as observed from Earth. The diagram follows the phases as described by William of Conches, including: the new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, and waning crescent.

This work is recovered from the binding of a later book: vellum was often reused as it was precious material.

T-O world map and astronomical diagram of lunar phases, both measuring 50mm in diameter. The work is presented on vellum, and features red ink with yellow and green gouache; captions in brown ink; proto-gothic script written in two columns, on bifolium (pair of folio-sized leaves, or two-page spread) recovered from binding.

This rare medieval world map and lunar chart, which is presented on a loose bifolium, was lost in obscurity before it was recovered from binding material from a later book. The map was originally produced in northern France in the late-twelfth or early-thirteenth century, and derives from an illustrated manuscript by William of Conches titled the 'Dragmaticon Philosophiae' (c.1144–1148). 

In his writings, William discusses the natural world and celestial phenomena, including the moon. Lunar phases are illustrated in a diagram in the lower right corner of this extract. His work was part of the broader medieval attempt to understand astronomical events in a way that integrated classical knowledge with contemporary medieval thought.

The upper left of the bifolium shows includes a rare example of a medieval T-O map: the globe is divided into four continents instead of the traditional three, suggesting that the mapmaker may have been referring to the work of Beatus of Liébana (c.730-798 CE), whose maps were reproduced throughout the twelfth century. This depiction may also be influenced by the cosmological treatise of Jewish-Persian scholar, Masha’Allah ibn Athari (c.740-815 CE).

William’s 'De Philosophia Mundi' (published c.1130) was inspired by Plato's 'Timaeus' (c.360 BCE) and heavily influenced by Neo-Platonic ideas. The work contested literal interpretations of the Biblical Book of Genesis, including the theory that Eve was made from Adam’s rib. In response to his work, William faced charges of heresy and was subsequently forced to revise and republish the 'De Philosophia Mundi' as the 'Dragmaticon Philosophiae' between 1144 and 1148. 

The rendering the spherical T-O map as a 'quadripartite', or four-continent, globe could relate to the cosmological treatise of Jewish-Persian scholar Masha’Allah ibn Athari (c.740-815 CE), who was also considered a heretic by William's accusers.

An extremely rare bifolium (two-page spread) from a late twelfth or early thirteenth-century manuscript copy of William of Conches’s 'Dragmaticon Philosophiae'. The work includes a T-O world map and a celestial chart showing the phases of the moon. The T-O map follows the ancient doctrine of the Earth split into the three continents of Asia, Africa, and Europe, bounded by waterways. 

An Early Thirteenth-Century T-O Map by William of Conches