Swedish Karl Gustav
born 1622
died 1660
King of Sweden (1654–60).
Nephew of Gustav II Adolf , he failed in his efforts to marry the Swedish queen Christina , but she named him to succeed her. As king he attempted to restore the public finances but was forced to devote most of his attention to military matters. He conducted the First Northern War (1655–60) against a coalition that eventually included Poland, Russia, Brandenburg, the Netherlands, and Denmark, with the aim of establishing a unified northern state. After conquering Poland (1655–56), he won back lands in southern Sweden from Denmark by the Treaty of Roskilde (1658).