"In this place, a poverty-stricken tribe lives on high terps and hand-built platforms, which raise their homes above the known high water mark. When the waves wash over the surrounding land, the inhabitants look like seafarers, but when the water subsides they have the appearance of shipwrecked people." That's how a Roman officer described the people living on the shores of the North Sea. To him and his comrades, this was the edge of the world. In the sea, he expected to find fabulous monsters, and on land, savage barbarians. Every ancient author writing about the Low Countries, was...