Sten Sture had been elected as Lord Protector of Sweden by the Riksmöte in Arboga in May 1471.

Advocating Swedish secession from the Kalmar Union, Herr Sten as he is known, has garnered large support.

In particular his followers are to be found among the peasantry, in Stockholm and in the Bergslagen mining region.

The latter region's trade with German cities such as Lübeck had often placed its residents in conflict with Union's Danish foreign policy.

In response to the election of Sture, Christian I sails to Sweden with a military force, intending to unseat him as Lord Protector.

Mooring his ships off Skeppsholmen in Stockholm, he sets up camp on Brunkebergsåsen, a ridge a short distance north of Stockholm (at the time Stockholm is restricted to the island containing the Old Town).

On Thursday, October 10, Sten Sture and Nils Bossom Sture lead their troops north to the area which is Hötorget in Stockholm today, near Brunkeberg.

Sten Sture's battle plan is to catch Christian's troops in a vice; Sten attacks from the west, Nils from the east, and Knut Posse strike south from the city itself.

In the ensuing battle, Christian is hit in the face by musket fire.

Losing several teeth, he is forced to retire from battle.

The decisive turn of battle in favor of Sture's side occurs when Nils' troops break out of the forest north of the ridge, as Posse's troops attack from the city.

This cuts off a contingent of Danish troops at the Klara monastery north of the town.

Christian retires with his troops towards the island of Käpplingen (today the Blasieholmen peninsula); however, Sten's troops destroy the makeshift bridge Christian's troops had built, causing many to drown.

The battle ends in a victory for Sten Sture, whose power as regent of Sweden is thus secured and will remain so for the rest of his life.

According to legend, Sture had prayed to Saint George before the battle.

He later paid tribute to Saint George by commissioning a statue of Saint George and the Dragon carved by the Lübeck sculptor Bernt Notke for the Storkyrkan church in Stockholm, as an obvious allegory of Sture's battle against Christian.

An altar dedicated to Saint George was also built in the church.