The Treaty of Roskilde was negotiated at Høje Taastrup Church and signed (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.

The Second Northern War (1655–60), was fought between Sweden and its adversaries the Polish–Lithuanian Commonwealth (1655–60), the Tsardom of Russia (1656–58), Brandenburg-Prussia (1657–60), the Habsburg monarchy (1657–60) and Denmark–Norway. The Dutch Republic waged an informal trade war against Sweden and seized the colony of New Sweden in 1655, but was not a recognized part of the Polish–Danish alliance.