Øresund

The Sound separates Zealand from Scania and forms one of the principal entrances to the Baltic. At its narrowest, between Helsingør and Helsingborg, the shores are only a few kilometres apart. In 1429 King Eric of Pomerania began collecting dues from foreign ships passing through, creating an enduring source of revenue for the Danish crown. The fortress later known as Kronborg guarded the passage, whose control became a matter of trade, diplomacy and war.