by The Cartographic Entrepreneurs of the Medieval Mediterranean
This nomination for the workshops of cartographers, primarily in Genoa, Venice, and Majorca, who from the 13th century onward produced portolan chartsthe first truly practical nautical maps for sailors. These were not symbolic or theological maps but detailed, accurate coastal outlines of the Mediterranean and later the Atlantic coasts, crisscrossed with a web of rhumb lines radiating from compass roses. These lines allowed a navigator to plot and maintain a constant bearing. The charts were closely guarded trade secrets, highly valuable information goods produced for commercial and state clients. Their creation relied on aggregating the experiential knowledge of countless pilots and captains. The portolan chart makers demonstrated that accurate geographic information, systematically compiled and presented in a usable format, was a saleable commodity of immense strategic and economic value. They proved that the safety and efficiency of maritime trade depended on high-quality, specialized data, and that a business could be built on synthesizing and selling that data to those who needed to manage risk at sea.
