Popular Mechanics (South Africa)
TABULA ROGERIANA
AN UPDATE FOR THE NEXT MILLENNIUM
The Tabula Rogeriana, or Book of Roger, was completed by Moroccan cartographer Muhammad al-Idrisi in 1154. Compiled over 15 years for King Roger II of Sicily – who hoped the map could inform and expand his rule – the book included a world map with 70 regional maps, each accompanied by a detailed description of their cities, roads, rivers, and mountains. For the next three centuries, it was among the most accurate geographic works in existence of the known world. It later helped guide Vasco da Gama’s voyage to India by sea.
Though it was produced for a Norman king in Italy, the atlas was a culminating achievement from the Islamic Golden Age – while science took a sabbatical in most of Europe during the early Middle Ages.
Al-Idrisi’s work was in large part based on Geographia, which was rediscovered and translated into Arabic around the 9th century. Islamic cartographers built on Ptolemy’s work and corrected errors based on their knowledge of the growing empire. They accurately drew the Indian Ocean as open and connected to the Pacific Ocean, instead of Ptolemy’s landlocked sea.
Islamic map-makers also produced some of the most elaborate charts of the era, largely inspired by the need to determine the direction of Mecca from anywhere in the world. Islamic world maps were orientated with south at the top, looking ‘up’ towards the holy city.
The famous warning ‘Here be dragons’ is a map myth: It was never actually written on old maps, though a Latin version appears on one 16th-century globe. Instead, the phrase represents the illustrations of monstrous sea serpents, toothy beasts, and strange peoples that frequently adorned medieval and Renaissance maps.
In most cases, map monsters were simple decoration, strategically filling in the empty parts of the map. (Cartographers are known to abhor a blank space.) But often, these imaginary beasts were seen as very real threats, born out of inflated travellers’ tales and infused with religious myth and folklore. They were often drawn lurking in uncharted waters, where they signalled the dangers that lie beyond the known world.
On some of the medieval world maps, the inhabitants of distant lands are depicted as strange mythical peoples. You’ll find the headless ‘blemmyes’ with faces located in their chests, the desert ‘sciapods’ with a single giant foot to shield the sun, and the ‘antipodeans’ who live on the other side of the world (the Australian continent from the Europeans’ perspective) and whose feet point in the opposite direction.
Ancient sailors navigated the seas by keeping in sight of land and observing the sun and stars. If clouds rolled in, they pulled in their sails and waited for better visibility.
The discovery of the compass – a magnetised needle on wood, floating in water, aligning itself with the magnetic poles – changed navigation. Sailors could safely venture into the open sea without visual cues.
First mentioned in 11th century China, the compass spread along the Silk Road connecting the East and West, and with it, a new type of European map came into vogue, called a portolan chart. These nautical maps were covered in criss-crossed lines indicating the bearings of trade routes between ports. The oldest surviving example, the Carte Pisane, dating to 1290, charts the
Mediterranean and Black Sea with enough accuracy that ships could navigate with it today. But the most famous and expansive portolan map is the Catalan Atlas. Drawn over eight pages of vellum in 1375 by Majorcan cartographer Cresques Abraham, it was the first world map to include the compass rose and stretched from the western edge of Europe and North Africa to China’s eastern coast.