Ecomare

During the Bronze Age, a Germanic folk built terpen (dwelling mounds) in the peat bogs and marshlands of the North Netherlands. The Romans called them Frisii. In the first half of the Middle Ages, the bogs were washed away in an increasing degree, so that eventually a sea formed, called the Middle Sea, which divided the Frisian land into Oostergo and Westergo. Eventually, the Frisians began building polders and reclaimed the entire Middle Sea. The northern part of this reclamation is called the Bildt.