Having seen the Carta Pisana as young student in the Bibliotheque Nationale de Paris in 1981, I planned to write a blog about cartography this summer. The map is called Carta Pisana because it was found in Pisa. But it was most likely drawn in 1275 in Genoa, which had taken over from Pisa as pre-eminent power in the Western Mediterranean. The Carta Pisana is the first of a new type of maps called Portolan which blend geographical information with information on wind direction and local harbors. The map's origin from Genoa, one of two centres of trading, makes perfect sense.
Redrawing of the Carta Pisana – the original is on parchment and difficult to read
The map covers the Mediterranean, the Black Sea, the coast of North Africa down to the 33rd Parallel and England. It is amazingly accurate for places in the Mediterranean and the Black Sea deviating on average by only 1% from the true location. The locations on the Atlantic and England lack this accuracy though. Maps were compiled by diligently assembling thousands of ship logbooks from their owners extracting locations, directions, journey times and wind speeds. Since Europeans used compasses after 1200 AD, directional information was finally accurate. Compass readings are not subject to individual judgements. They are what they are.
Tabula Rogeriana made by Muhammed Al-Idrisi for King Roger II of Sicily in 1154
Logbooks from ships were not the only sources though. As we have seen with Algebra, travellers like Fibonacci from Pisa copied interesting documents, translated and brought them to Europe. We do not know whether the map makers of Genoa had access to such precious pieces like the Tabula Rogeriana, which was made based on information from Muslim merchants and travelers. But it would not surprise me if a copy of Roger’s map had found its way to Genoa. In 1275, Genoa was at the peak of its power and would put its hands on anything that was useful for its Empire. Maps were not made for pilgrims but for the purpose of state: for merchants to reach their destinations faster and for navies to conduct their campaigns more efficiently.
Sadly, my research project on Genovese map makers did not get far. There are very few sources in English and with Covid-19 I could not travel to Genoa. Am sure I would have found more material looking in local libraries. But it was definitely a big business. We know from Christoph Columbus’s biography that he loved comparing maps and would spend hours poring over them as a young man. Studying maps and old texts on geography inspired him to his project of sailing to India on a westerly course. He knew the world was round and that both sailing east and sailing west would eventually lead to the same destination. What he did not know was that another continent was in between.
Abraham Cresques, Jewish map maker in Palma, made this Catalan Atlas in 1275
Luckily, we know a bit more about the Majorcan Cartographic School which emerged from Jewish cartographers and nautical instrument makers. Through their Jewish network they had access to information which otherwise was only in the hands of the elites in Genoa and Venice. They became the map makers of the Kings of Aragon and were critical in Aragon’s expansion into the Mediterranean. The Majorcan School dominated European map making from the 13th to 15th century. The most important maps were made in Palma or by disciples of the Majorcan School working in Venice, Genoa, Rome and Constantinople. Maps were now enriched with content about the inlands, colored and carried more information about coastlines and harbors. They became a tool you could navigate with when combined with a compass. Mariners appreciated their accuracy and copied them whenever they could. The mass production of maps had to wait for the printing press though which was invented in 1440. It could print 3’600 pages per workday – making a manual copy took a full day. Finally, geographic information could be distributed.
Expansion of Aragon in from the 13th to 15th century
The Majorcan School of map making changed world history in another context as well. When Ferdinand II from Aragon married Isabella I from Castile in 1469, he brought a valuable piece of dowry to the new Spanish State – the art of cartography which underpinned the age of exploration and the subsequent foundation of the Spanish Empire. Not that the Empire was grateful for the gift from the Jewish community. The Majorcan Jews were expelled from Spain as all other Jews in 1492. The happy beneficiary was the Ottoman Empire. This transfer of soft power enabled it to become a maritime power quickly and to stop the Spanish Expansion into the Mediterranean. Seems that every bad deed gets punished!