In the Second Northern War from 1655 to 1660, during the reign of Charles X, Sweden was set on expansion. Through military action, Sweden rapidly became the strongest military power in the north. Frederick III was suffering under the humiliating loss of traditional Danish provinces to Sweden in 1645. As Charles X appeared to be fully occupied in Poland, Frederick III judged the time appropriate for recapture of the other Danish-Norwegian provinces. The King’s Council agreed to war, a decision that led rapidly to ruin.