The Map That Put South on Top

A Muslim geographer working for a Christian king produced the most accurate map of the medieval world. He drew it upside down. South was at the top. Europe was a fringe at the bottom. Africa and Asia dominated the centre. The map was correct. The orientation was a statement.

The story of how a Moroccan scholar ended up in Sicily, and what he built there, tells you something about the 12th century that the 21st has mostly forgotten.

Roger commissioned the project. He wanted a comprehensive map of the known world, and he was willing to pay for it. For fifteen years, al-Idrisi gathered existing maps, interviewed travellers, and sent expeditions to confirm reports. He drew on three centuries of Islamic cartography — a tradition unknown in Western Europe — as well as Ptolemy's Geography, translated into Arabic centuries before anyone in Paris could read Greek.

The result, completed in 1154, was the Tabula Rogeriana: a world map engraved on a silver disc six feet in diameter, weighing 450 pounds. A silver globe accompanied it. Alongside these was a book titled, with the modesty of an era that had not yet discovered understatement, "The Pleasure Excursion of One Who Is Eager to Traverse the Regions of the World." It contained 70 sectional maps and detailed descriptions of each region.

The map was oriented south-up, following Islamic convention. It showed Europe, Asia, and North Africa in detail — including the source of the Nile, which al-Idrisi placed in central Africa with an accuracy that European explorers would not match for another 700 years. The map was wrong about many things. It was more right than anything else available, which is the definition of the best map at any given moment.

Al-Idrisi's legacy is cartographic but also cultural: a Moroccan Muslim who worked for a Christian king, used Greek science preserved in Arabic, and produced a work that Europe relied on for three centuries. The silver disc was destroyed when the Normans lost Sicily. The book survived. The maps were copied, translated, and consulted by explorers who had never heard of Ceuta and could not have found it on a map — unless they were using al-Idrisi's.