Treaty of Roskilde

The Treaty of Roskilde was negotiated at the parsonage of Høje Taastrup Church and was concluded on 26 February (OS) or 8 March 1658 (NS) in the Danish city of Roskilde during the Second Northern War between Frederick III of Denmark–Norway and Karl X Gustav of Sweden. After a devastating defeat, Denmark–Norway was forced to give up a third of its territory to save the rest, the ceded lands comprising Blekinge, Bornholm, Bohuslän, Scania and Trøndelag, as well as Halland.

After the treaty entered into force, Swedish forces continued to campaign in the remainder of Denmark–Norway, but had to withdraw from the Danish isles and Trøndelag in the face of a Dano–Norwegian and Dutch alliance. The Treaty of Copenhagen restored Bornholm to Denmark and Trøndelag to Norway in 1660, while the other provinces transferred in Roskilde remained Swedish.