August 13 In Swedish History
1645: In effect paving the way for modern Sweden a peace treaty in Brömsebro between Sweden and Denmark-Norway is signed.

The Peace of Brömsebro (Freden i Brömsebro) is signed, thus ending the Torstenson War, which had begun as a local conflict in 1643 and was part of the larger Thirty Years’ War between Sweden and Denmark-Norway. Negotiations for the treaty had begun in February the same year. The treaty resulted in Denmark-Norway ceding the provinces of Jämtland, Härjedalen, and Idre and Särna as well as the Danish Baltic Sea islands of Gotland and Ösel to Sweden. The Danish heir to the throne, Frederick II Administrator of the Prince-Bishopric of Verden (1634-1645) and of the Prince-Archbishopric of Bremen (1635-1645), had to resign, with the two prince-bishoprics being occupied by the Swedes.
Sweden was exempted from the Sound Dues, a toll on foreign ships passing through Danish waters into the Baltic Sea, and Hamburg was exempted from the “Elbe dues,” a toll levied until then on ships to that city by the Prince-Archbishopric of Bremen.
Sweden also received the Danish province of Halland for a period of 30 years as a guarantee of these provisions.


This treaty was to be followed by the Treaty of Roskilde in 1658, which forced Denmark-Norway to even further concessions in Sweden's favor.