Kalmar War

Date	1611-1613
Location	Border between Denmark and Sweden
Result	Dano-Norwegian victory; Älvsborg Ransom (1613)

Belligerents

Swedish Empire

Denmark–Norway

The Kalmar War (1611–1613) was a war between Denmark–Norway and Sweden. Though Denmark soon gained the upper hand, it was unable to defeat Sweden entirely. The Kalmar War was the last time Denmark successfully defended its dominium maris baltici against Sweden, and it also marked the increasing influence of the two countries on Baltic politics.

Since Denmark–Norway controlled the strait between the Baltic Sea and the North Sea, Sweden sought an alternative trade route through sparsely populated Lapland to avoid paying Denmark's Sound Dues. In 1607, Charles IX of Sweden declared himself "King of the Lapps in Nordland" and began "collecting" taxes in Norwegian territory, even south of Tromsø.

Since the Sound Dues were Denmark's main source of income, Denmark did not want to see alternative trade routes established, particularly when established through Norwegian territory. Denmark protested.

King Charles IX of Sweden ignored the protests of King Christian IV of Denmark and Norway. Finally, in April 1611, in response to Sweden's claim of a traditionally Dano-Norwegian area in Northern Norway, Denmark declared war upon Sweden and invaded.

The Danish side planned to attack Sweden on three fronts; from Kristianopel towards Kalmar, from Halmstad towards Jönköping and from Norway towards the fortress of Älvsborg and thereafter further into Västergötland.

A force of 6,000 Danish troops laid siege on the city of Kalmar, ultimately taking it. Unlike the swedish forces, the Danes did not participate with mercenaries due to Christian IV distrust in foreigners. Norwegian forces, although stationed on the border, were instructed not to enter Sweden.

...
Wikipedia