Medieval sea-charts – centuries before their time
It’s hard to describe the appearance of a portolan chart – the medieval answer to the modern Admiralty chart – if you haven’t already been able to see one. Very few early examples are freely available online but you can find a chart of 1403 here: http://brbl-dl.library.yale.edu/vufind/Record/3521236. Probably originating in the 13th century, though not everybody agrees about that, the portolan charts present the Old World with immediate recognisability. Covering the coastlines of the Mediterranean and Black Seas, along with the Atlantic shoreline up to Denmark (and the British Isles), they contradict every normal preconception about medieval cartography. You don’t need to have Italy, the Nile delta, Crimea and so on pointed out. They are where you would expect and pretty much how they ought to be.
The toponymy for some of the portolan regions have already been documented in detail (N.E. Spain, the Adriatic and the Black Sea). Besides what is being extracted from the original documents by the Pelagios team, the remainder will be sourced from a comprehensive listing that was compiled originally in preparation for a chapter in Volume 1 of The History of Cartography(University of Chicago Press, 1987) and then fleshed out and expanded over recent years. The resulting Excel spreadsheet is publicly accessible at http://www.maphistory.info/PortolanChartToponymyFullTableREVISED.xls, where it forms part of a detailed ongoing investigation into the portolan charts (http://www.maphistory.info/portolan.html).
**Former map librarian of the British Library (1987-2001), since 1993 Tony Campbell has been chairman of Imago Mundi Ltd, in which capacity he acts as co-ordinator for the biennial International Conference on the History of Cartography. He is working on Pelagios 4 as the expert adviser on portolan charts.