Eric of Pomerania, who was previously king of the Kalmar Union, had been exiled to the island, and was now ruling it, which, according to the Swedes, rightfully belonged to Sweden.

[1] Eric had also previously taken 7 ships from Stockholm loaded with iron, copper, butter, and hides that were originally going to the Hanseatic states, which made Charles want to take revenge on him.

[1] In mid-August, the Gotland countryside was fully occupied by the Swedes, Visby was also quickly surrounded by Magnus Gren and the Swedish fleet blockaded all shipments.

[2] In January 1449, the Gutes formally pledged their allegiance to Charles with the justification that Gotland "formerly belonged to Sweden's crown by right, according to what our chronicle clearly proves, and certificates".

Charles proposed that the Gotland issue was to be solved judicially with representatives from the Hanseatic cities, and in the summer, the Swedes prepared to storm Visby.