The Dutch–Hanseatic War was a conflict between the County of Holland, acting independently of the rest of the Burgundian Netherlands of which it formed part, and the Hanseatic League. It led to little actual fighting, with a Dutch fleet patrolling Øresund while a Hanseatic fleet blocked their access to the Baltic Sea. It ended after Eric of Pomerania was forced from the throne of Denmark in 1440, and the new king Christopher of Bavaria sought a resolution. Peace was concluded in 1441 with the Treaty of Copenhagen.
Background
The Dutch–Hanseatic War was a war of trade competition and control of Baltic shipping. For several years, tensions between Dutch and Hanseatic traders had risen as the Hanseatic traders struggled to keep Dutch trade with Livonia limited. In response, the Dutch had begun employing privateers against German shipping.
Events and resolution
On 14 April 1438 a formal war was declared by the Dutch administration against the six Wendish cities of the League—Hamburg, Lübeck, Lüneburg, Greifswald, Stettin (now Szczecin) and Anklam—and the County of Holstein, and on 23 April the Hanseatic League informed its member cities of the situation and advised shipping via Flanders, rather than Holland or Zeeland. Little actual fighting took place throughout the war, though in May 1438 the Dutch mobilised all suitable ships in Holland and ordered the construction of 79 new vessels. During much of 1438–1440, the Dutch fleet patrolled Øresund but didn't manage to penetrate deeply into the Baltic Sea itself, as the Wendish fleet managed to block the passage. The State of the Teutonic Order however declared itself neutral, and the cities in Prussia refused any military assistance to support the Hanseatic war effort.
When Eric of Pomerania was forced from the throne of Denmark in 1440, an opening for a settlement with the new king Christopher of Bavaria presented itself. Though nominally allied with the Hanseatic cities, he favoured reconciliation and a solution to the conflict, and even awarded Dutch traders the same rights as Hanseatic traders in Denmark. In September 1441 a peace settlement was made through the Treaty of Copenhagen. The settlement meant that the two parties granted each other free trading rights, which gave the Dutch unrestricted access to trade on the Baltic again. This was to be of long-term benefit for the Dutch rather than the German cities, but the peace settlement also contained costly reparations which the Dutch had to pay.