King Christian II and his ally, the Swedish ArchbishopGustav Trolle, the scion of a prominent unionist noble family, had tried to eliminate the separatist Sture party among the Swedish nobility by executing a large number of them in the Stockholm Bloodbath. The King was also unpopular for imposing high taxes on the peasantry. Furthermore, German and Danish nobles and commoners held most Swedish castles and this provoked the native Swedish nobles.
Rebellion
The war started in January 1521 when Gustav Vasa was appointed hövitsman over Dalarna by representatives of the population in the northern part of the province. After Gustav Vasa sacked the copper mine of Kopparberg and the town of Västerås, more men joined his army. In 1522, the Hanseatic city of Lübeck allied with the Swedish rebels. After the capture of Stockholm in June 1523, the rebels effectively controlled Sweden, and on 6 June Gustav Vasa was elected King of Sweden in the town of Strängnäs. By September, Swedish Finland was also controlled by Gustav Vasa's supporters. By the Treaty of Malmö signed on 1 September 1524, Sweden seceded from the Kalmar Union.
Dalarna
In 1520, Gustav Vasa traveled to the Swedish province of Dalarna, disguised as a farmer to avoid detection by King Christian's scouts. In December, Gustav Vasa arrived in the city ofMora, where he asked the peasantry for their help in his revolt against Christian II. The peasants refused his request, so Gustav Vasa decided to travel north to find men who would support his revolt. Shortly thereafter, a couple of refugees arrived in Mora, where they told the peasantry about the brutality of Christian II and his men. The people of Mora then decided to find Gustav Vasa and join his revolt. They sent two skilled skiers to find him. In Sälen, they finally caught up with him. Back in Mora, on New Year's Eve, 1521, Gustav Vasa was appointed to "hövitsman" by envoys from all the parishes of North Dalarna. In February, Gustav Vasa marched out from Mora with about 100 men and sacked Kopparberg. Shortly thereafter, the peasantry of Bergslagen joined the revolt. Gustav Vasa's army had now grown to over 1,000 men.
When news of the Swedish revolt reached Christian II, he sent a force of Landknechten to crush the rebellion. In April 1521, the union forces confronted Gustav Vasa's men at Brunnbäck Ferry, and the King's army was crushed. This victory greatly improved the Swedish rebels' morale. In Dalarna, an emergency mint was established in order to produce the copper coins necessary to finance the war.
Västerås
The rebel army continued south to Västerås, which they conquered and sacked. When words of Gustav Vasa's success spread across Sweden, the supporters of the Sture family decided to join the revolt. By the end of April 1521, Gustav Vasa controlled Dalarna, Gästrikland, Närke, and Västmanland.
