The most celebrated topological diagrams to survive from the Roman past are sling-shaped charts, of which at least two are preserved as they would have been used in late antiquity and seemingly without any medieval additions:
These charts, each with several dozen places named on them, should be
distinguished from T-O diagrams and other tiny schematics scrawled in the
margins of books. Medieval practice was to lump all of these objects
together under one term, mappaemundi
, without any mind to their very
different diagrammatic qualities. This portal looks back to the pre-medieval
past and avoids use of the neo-Latin term mappamundi except where it
is the established name of a particular diagram.
The Vatican Mappamundi comes the closest among all the late-antique cartographic drawings to a classical mental representation of the known inhabited world as having the shape of an open sling. This notion originated by Poseidon of Apamea was reported by Dionysius Periegetes and described the oikumene thus:[*]Translation by I.G. Kidd (Cambridge, 1999) from a fragment by Eustathius, on Attalus.org. The simile has been offered in elucidation of the Albi Mappamundi by both Patrick Gautier-Dalché and Anca Dan.
This is the shape of the inhabited world, according to Poseidonius. The world can be divided into two cones, as Dionysius [Periegetes] says later on. One of the cones contains Asia, and the other consists of Europe and Africa. The pointed ends of this inhabited "sling" are towards the east and the west; he calls these the pathway of the sun. The broader ends are towards the north and the south. Therefore, as the two cones are joined together at the base, their narrow peaks lie towards the east and the west, while their wide bases lie towards the south and the north.
The sling is a trapezoid piece of cloth used to lift a heavy object or secure a broken arm. The shape allows Europe, Asia and Africa to be arranged as distinct landmasses around the Mediterranean.
This is also the objective of the tiny schematics, also known as mappaemundi, which show the three continents as parts of a quartered circle, whereby Asia always occupies two quadrants. But in terms of operative visualization, the two sorts of diagram are very different from one another.
The Library of Latin Diagrams by Jean-Baptiste Piggin is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.