The Treaty of Roskilde (concluded on 26 February (OS), or 8 March 1658) (NS) during the Second Northern War between Frederick III of Denmark–Norway and Karl X Gustav of Sweden in the Danish city of Roskilde. 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 (Båhuslen), Scania (Skåne) and Trøndelag, as well as her claims to 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 face of a Danish–Norwegian–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. Background As the Northern Wars progressed, Charles X Gustav of Sweden crossed the frozen straits from Jutland and occupied the Danish island of Zealand, with the invasion beginning on 11 February 1658. A preliminary treaty, the Treaty of Taastrup, was signed on 18 February 1658 with the final treaty, the Treaty of Roskilde, signed on 26 February 1658. Although Sweden also invaded Romsdal in western Norway, the local farmers rebelled and defied the Swedish taxes and military conscription vigorously. The Swedish governor was forced to send a full company of soldiers and 50 cavalry to collect taxes. The action was not successful, and the area remained largely autonomous. Provisions The treaty's conditions included: The immediate cession of the Danish province Scania (Skåne) to Sweden. The immediate cession of the Danish province Blekinge to Sweden. The immediate cession of the Danish province Halland, which under the terms of the Peace of Brömsebro, negotiated in 1645 was then occupied by Sweden for a term of 30 years, to Sweden. The immediate cession of the Danish province of Bornholm to Sweden. The immediate cession of the Norwegian province of Bohuslän (Båhuslen) to Sweden. This effectively secured for Sweden unrestricted access to western trade. The immediate cession of the Norwegian province of Trøndelag, then including Nordmøre and Romsdal, to Sweden. Danish renunciation of all anti-Swedish alliances. Danish prevention of any warships hostile to Sweden passing through the straits into the Baltic. Restoration of the Duke of Holstein-Gottorp to his estates. Danish payment for Swedish occupation forces costs. Danish provision of troops to serve Charles in his broader wars. Aftermath Copenhagen The Swedish king was not