The Cartographer Sets Sail: Eyewitness Records and Early Modern Maps

In this article I examine early nautical charts and isolarii, or island books illustrated with maps, for evidence that indicates the maps were made on the basis of first-hand observation by the cartographer. There are very few claims on early nautical charts that the charts were created based on the cartographers’ own observations. I suggest that these claims are rare because chart-making was more an artistic enterprise than as a medium for recording discoveries. This conception of nautical charts changed with the advent of the Age of Discoveries, and claims that charts were made based on eyewitness information become more common. The case with isolarii is very different, although the maps in isolarii derive from the nautical chart tradition. Some of the creators of isolarii claim that their works were based on first-hand experience, but not always truthfully. Other authors neither sailed among the islands they describe nor claim to have visited them.