At the end of the 15th century the King of Denmark and head of the Kalmar Union John (Danish: Hans) faced rebellion from Sweden.

The news quickly spread to many Swedish nobles who saw this as an opportunity to break with Danish rule, and in August 1501 an uprising thereof broke out.

[2] John hurried to Denmark in order to raise an army, while Queen Christina of Saxony would defend Tre Kronor castle and Stockholm.

Led by Johan von Grapendorf, they consisted of a large number of German and Danish mercenaries, but they also included many Swedish Unionists.

[4][2] The Swedish forces were led by clergyman and bishop of Linköping Hemming Gadh and together mustered 4,000 peasants,[2] awaiting another 1,400 Dalarian shooters.

[5] On 2 February 1502, he wrote to Henrich Krummedige: Every day We endeavor with the help of God to go to Stockholm as soon as the waters are free in order to help and rescue our dear wife and the people.Finally, on 13 March, the king appointed commanders for the fleet, yet the departure was delayed for another two weeks.

[5] In order to hinder the Danish fleet from arriving, the Swedes placed a boom between the city and a small island called Käpplingeholmen, yet the project failed because of the heavy stream.