The Dano-Swedish War (1657-1658) was a conflict between the Kingdom of Denmark-Norway and the Kingdom of Sweden. It arose from territorial disputes and Denmark's desire to regain influence in the region. The war was marked by several battles, with Sweden initially gaining the upper hand. The conflict ended with the Treaty of Roskilde in 1658, which resulted in significant territorial losses for Denmark. Sweden gained control over important regions, including Skåne, Blekinge, and Halland, solidifying its power in Northern Europe and altering the balance of power in the region.