Jade Bay

Jade Bay opens onto the North Sea in northwestern Germany, on a coast repeatedly remade by storm floods. Before the great medieval incursions, much of the area was low ground with peat bogs and scattered higher islands. The Second Marcellus Flood of 1362 destroyed villages and enlarged the inlet westward. Further disasters culminated in the flood of 1511, when the bay reached its greatest extent.

Afterward, improvements in the organization and construction of dikes gradually allowed reclamation to exceed the loss of land. Embankments of the sixteenth and seventeenth centuries reduced the bay toward its later outline, transforming former tidal ground into protected country. Around 1700 most of the shore was enclosed, but a difficult gap remained on the southeastern side between Schweiburg and Hobenbrake. Under Christian Thomesen Sehestedt, the Oldenburg governor serving the Danish crown, this final gap was closed between 1721 and 1725. Part of the surviving raised bog was left outside the dike. The bay's early modern history was therefore written through specific losses, new embankments and the difficult work of holding a boundary between land and sea.