The ‘Dragmaticon Philosophiae’, a treatise on natural philosophy, was first written by Conches between 1144 and 1148. About eighty meticulously copied manuscript versions were circulated over the next four hundred years before it was first printed in 1567 in Strasburg by Josiah Rihel. 



 (1090–c.1155) was born by his own account “in a country of mutton-heads” (‘Dragmaticon’ VI.i.i.), and left to study under Bernard of 

res. He taught at the Universities of Paris and 

res and eventually became a tutor to the children of Geoffrey Plantagenet, including the future Henry II of England. He is best known for his early work ‘Philosophia Mundi’ (c. 1125), and the later modified version, ‘Dragmaticon Philosophiae’ (c. 1144), from which these leaves derive. 

This map repeats much of the 'T-O' template: it depicts the habitable world as a circle oriented with East ('Oriens') at the top, West ('Occidens') at bottom, South ('Septentrio') to the right and North ('Auster') on the left. The map is encircled and divided into two hemispheres by the ocean. The vertical line of the 'T' represents the Mediterranean Sea; as for the horizontal line, the left half traditionally represents the Don River (and the Sea of Azov, Black Sea, Sea of Marmara, and the Aegean Sea), while the right half represents the Nile. The Indian and Mediterranean Oceans are named, as are Africa, Mount Calpe (the Rock of Gibraltar), and Spain. The map also shows a mysterious fourth continent to the south of Africa, suggesting a cartographic lineage that traces back to by Spanish geographer, Beatus of Lieban who created ‘quadripartite’, or four-contentment maps based on Islamic sources.
There is disagreement as to whether the T-O map as a genre represents a flat or spherical Earth. However, most educated scholars, like 

 were aware of the spherical nature of the earth. Elsewhere in a separate ‘Tract on the Philosophy of Man’, the author spiritedly states the Earth is round and provides diagrams to demonstrate its shape (e.g. London, British Library, Arundel MS 377, f. 131v). In general, medieval belief in a flat Earth has been greatly exaggerated and was first popularized by nineteenth-century works of fiction such as Washington Irving’s pseudo-biography of Christopher Columbus (1828).

Early classical scholars knew that the earth was spherical and that lunar eclipses occurred when the Earth passes between the Sun and the Moon. Yet, the earliest surviving maps from the Medieval world, 'mappae mundi' (singular 'mappa mundi'), were not designed with geographical accuracy in mind. Rather, they illustrate Judeo-Christian beliefs and theoretical concepts. Some were purely diagrammatic such as the climate zone maps based on the work of Roman commentator, Macrobius (fl. 400). Others like the T-O maps presented highly schematized illustrations of the three known land masses: Europe, Asia, and Africa. The ‘T’ shape of the T-O map may have been derived from the Greek 'tau', an ancient form of the cross that was adopted by early Christians as a clandestine symbol of their faith. In a cartographical context, the tau superimposed on the map sets the Earth in a Christian worldview.

This rare example of a world map was illuminated in northern France in the late-twelfth or early-thirteenth century and preserves a cartographic genre, known as a 'T-O' map, on the top left. T-O maps were among the earliest attempts to project three-dimensional space on a flat plane.  Asia is shown on the right, Europe on the top left, and Africa on the bottom left, of this map. The second diagram shows the phases of a lunar eclipse with the sun on the right.

Showing four continents instead of the traditional three, this 'T-O' map likely derived from a copy of an earlier treatise of 

 known as the 'Philosophia mundi' (c. 1125). This early work was heavily influenced by neo-platonic ideas inspired by the ‘Timaeus’ and it ridiculed literal interpretations of the Biblical book of Genesis, including the theory that Eve was made from Adam’s rib. In response to his work, Conches faced charges of heresy and was forced to revise and republish the 'Philosophia mundi' as the 'Dragmaticon Philosophiae' in 1148. Though this map derives from the revised copy, it retains an original quadpartite design inspired from a cosmological treatise of Jewish-Persian scholar Masha’Allah ibn Athari (d. 815), considered a heretic by Conches’ accusers. Thus while Conches was forced to revise his text, the map continues to contradict the Biblical tradition of three separate continents and preserves a remnant of Conches’ original thought.

This superb example of a rare bifolium from a late twelfth- or early thirteenth-century manuscript copy of 

’s ‘Dragmaticon philosophiae’ includes an early example of a medieval world map and a celestial chart for lunar eclipses. The world map, commonly known as a ‘T-O’ map, illustrates an ancient doctrine of the earth split into the three continents of Asia, Africa, and Europe bounded by t-shaped waterways. 

T-O world map (diameter 50 mm) and astronomical diagram of a lunar eclipse (diameter 50 mm) on vellum, in red ink with yellow and green gouache, captions in brown ink, protogothic script written in two columns, on bifiolia recovered from binding. 


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