1660
Frederick III was suffering under the humiliating loss of traditional Danish provinces to Sweden in 1645. As Charles X appeared to be fully occupied in Poland, Frederick III judged the time appropriate for recapture of the other Danish-Norwegian provinces. The King’s Council agreed to war, a decision that led rapidly to ruin.
The Norwegian phase of the war went well. A Norwegian force of 2000 men recaptured Jemtland and Herjedalen. A Norwegian force set out from Bohuslen to join the Danish force invading Sweden from Skåne.
Reacting swiftly, by forced marches Charles X attacked Denmark with great success leaving the humiliated Danes with no choice but to sue for peace on any terms.
As a result, the Treaty of Roskilde was negotiated in 1658. The terms were brutal:
- Denmark ceded the provinces of Skåne, Blekinge and Halland
- Norway was forced to hand over Trøndelag and Bohuslen
- Closing of the Sound to non-Swedish warships
Charles X did not keep the peace and in the remainder of the war the Norwegian army successfully defended Norway from Swedish attacks and recaptured Trøndelag. In the Treaty of Copenhagen Norway kept Trøndelag but the other Norwegian provinces were to remain with Sweden.
Read more about this topic: Military History Of Norway, Northern War 1655