The battle was part of a long series of conflicts and civil wars between unionists and separatists during the Kalmar Union era in the 15th century.

[1] The young Bishop of Linköping, Kettil Karlsson of the Vasa family, took up arms and organised the uprising in Östergötland in the winter of 1463/1464, briefly laying siege to Stockholm before retreating in the face of Christian's army approaching from the south.

He then travelled to Dalecarlia and Västmanland, where he gathered an army largely made up of peasant militia and Swedish separatist nobles, among them the future Regent of Sweden, Sten Sture the Elder.

King Christian marched west from Stockholm and laid siege to Västerås Castle, which was held by Bishop Kettil's uncle, Nils Kristiernsson Vasa.

While initially successful against the militia, the Danish troops were drawn further into the forest, losing their cavalry advantage and forcing the knights to fight on foot.

[4] An attempt by unionists under Ture Turesson Bielke to land an army in Västmanland was defeated by Kettil Karlsson's separatists at Kvicksund.