Walcheren () is a region and former island in the Dutch province of Zeeland at the mouth of the Scheldt estuary. It lies between the Eastern Scheldt in the north and the Western Scheldt in the south and is roughly the shape of a rhombus. The two sides facing the North Sea consist of dunes and the rest of its coastline is made up of dykes. Middelburg, the provincial capital, lies at Walcheren's centre. Vlissingen, to the south, is the main harbour and the third municipality is Veere. Originally, Walcheren was an island, but the Sloedam, constructed in 1871 for a railway, and poldering after World War II have connected it to the (former) island of Zuid-Beveland, which in turn has been connected to the North Brabant mainland. History Early history As early as Roman times, the island functioned as a point of departure for ships going to Britain; it had a temple of the goddess Nehalennia who was popular with those who braved the waters of the North Sea. The Romans called it "Wallacra", a term most likely associated with Walhaz, the name Germans used for Romans. Walcheren became the seat of the Danish Viking Harald (fl. 841–842), who conquered what would become the Netherlands together with his brother Rorik (fl. 842–873) (or Rurik) in the ninth century. One fringe theory has it that Ahmad ibn Rustah (fl. 10th century) described Walcheren when reporting on the seat of the Rus' Khaganate. Another fringe theory mentions Walcheren as the seat of Hades, described by Homer. Treaty of Dover Under the Secret Treaty of Dover, concluded in 1670 between Charles II of England and Louis XIV of France, England was supposed to get possession of Walcheren as well as the isle of Cadzand, as the reward for helping France in the then impending war against the Dutch Republic. In the event, the Dutch resistance — much stronger than anticipated — managed to repulse the French-English attack, and the treaty was not implemented. Napoleonic Wars Starting on 30 July 1809, a British armed force of 39,000 men landed on Walcheren, the Walcheren Campaign, with a view to assisting the Austrians in their war against Napoleon, and attacking the French fleet moored at Flushing (Vlissingen). The expedition turned into a disaster—although Flushing surrendered the Austrians had already been decisively defeated at the Battle of Wagram in early July and were suing for peace.