The dominant Danish King along with archbishop Gustav Trolle of Uppsala would organize the beheading of anti-unionist bishops, noblemen & common enemies in the so called Stockholm Bloodbath that took place between 7–9 November of 1520, despite the promise given by King Christian II for general amnesty just before the surrender of the city.

The echo of the tragic event had the opposite result in the Swedish public opinion than what was expected by the Danish King. Gustav Vasa, son of one of the victims of the execution & heir to Sten Sture the Elder (nephew), traveled to the northern provinces of Sweden seeking support for vengeance and a new revolt. He finally succeeded in commencing the Swedish War of Liberation that would lead to the final end of Kalmar Union. Gustav Vasa’s election as a King in 1523 by the members of the Swedish Privy Council (Swedish nobles) was backed by the German councilors of the city of Lübeck. Later that year Gustav entered Stockholm triumphantly as King of Sweden installing himself in the Tre Kronor palace, the castle first built by Birger Jarl in the middle of the 13th century according to the tradition. In 1983, in remembrance of the election of Gustav as Swedish king on 6 June, that date was declared the National Day of Sweden.