The New Murrey and Blue blog

“….Where and how did medieval mapmakers, apparently armed with no more than a compass, an hourglass and sets of sailing directions, develop stunningly accurate maps of southern Europe, the Black Sea and North African coastlines, as if they were looking down from a satellite, when no one had been higher than a treetop?…”

I have just watched a small part of a TV documentary on Discovery Science (Series 1, Episode 6) in which it was shown how a man named John Hessler, an enthusiastic lepidopterist and curator at the Library of Congress, worked out how medieval mapmakers were able to be so incredibly accurate.

This amazing story prompted me to look further, and I came upon this site, which deals with Hessler’s discovery. (There’s much more on line elsewhere, but I found some of it a bit hard to understand!)

The site tells the intricacies of John Hessler’s discovery of how medieval cartographers were able to be so incredibly accurate. More detail elsewhere can make it all seem very technical and complicated, especially if, like me, you’ve got scientific or mathematical dunces for grey cells. Suffice it that Hessler used the patterns on the wings of Alpine butterflies to work out exactly how the first portolan map was created. Yes, really.

A quite astonishing story, and true!