Christian II had invaded Sweden in an attempt to preserve the Kalmar Union that joined the Scandinavian countries of Denmark, Sweden and Norway under a single monarch. Sweden’s anti-unionist party under the regent Sten Sture the Younger opposed the pro-Danish group who were nominally led by Archbishop Gustav Trolle.
Christian had twice failed to subdue Sweden before his successful invasion at the head of a mercenary army in early 1520. Trolle, who had been under siege since his removal from the office of Archbishop by Sten Sture, was soon reappointed. Having been hit by a cannonball that ricocheted into his leg at the Battle of Bogesund, Sture himself died of his wounds and the Swedish anti-unionist cause was severely weakened. Sture’s widowed wife held out against the invasion for a number of months, but she eventually surrendered and Christian was crowned King of Sweden on 4 November.
Three days later Christian invited a number of leading Swedes to a banquet at the palace. At dusk on 8 November his soldiers entered the building and arrested many of the guests. They had all been identified by Archbishop Trolle on a proscription list. Having been condemned to death as manifest heretics, around eighty people were drowned, hanged or beheaded by the Danes. Some sources also claim that Sten Sture’s body, along with that of one of his children, was also exhumed and burned.
The new king became known in Sweden as Christian the Tyrant, and before long he faced a new revolt under Gustav Vasa who led Sweden to victory in the Swedish War of Liberation.