A Danish force under the command of Otto Ruud snuck past Åbo's (Turku's) defenses at night, after which the Danes landed on the shore and spread out into the city.

In his report to Sten Sture the Younger on 16 August, Bishop Johannes Olvainpoika writes about how the Danes caused "immense and irreparable damage" during their attack on the cathedral.

[3] They spread out through the city, and eventually with a "horrible noise and with a terrible sound of drums and piercing trumpets" woke everyone up, in order to induce panic according to Bishop Juusten's chronicle.

They most likely attacked the town's cathedral first, stealing the bishop's mitre, crosier, aswell as books, copper, tin, iron, and items of all kinds.

[4] In a letter to regent Sten Sture the Younger on 16 August of the same year, Johannes Olvainpoika spoke of the Danes' actions in the cathedral.