Edward I's seven magnificent castles

The medieval Gough Map is the oldest recognisable map of Britain. No one knows who created it or why, but it represents a quantum leap in map-making, which previously had been largely theological.

One of the few accepted facts about the map, according to a book by Nick Millea, is that it was drawn in the mid-14th century. But it is possibly a copy of one created 70 years earlier, conceived as a work of propaganda to underline Edward I's claim to Wales and Scotland. The two major routes shown from England into Wales, for example, are precisely those used by Edward's invading armies. The more northerly one runs from Chester down to Cardigan, linking seven key castles – and it was this route I decided to try to follow.