The Consolidation of the Swedish Empire
The Peace of Westphalia (1648) helped to consolidate Sweden's status as a great power. However, Queen Christina's reign ended when she abdicated in 1654, in favour of her cousin, who would become Charles X Gustav. She may have abdicated due to her conversion to Catholicism and also due to her financially wasteful ways. Charles X Gustav had inherited a nation that was on the verge of turmoil, therefore, he spent his early reign trying to save Sweden from bankruptcy. He also had to improve his relationship with the nobility, as they had not supported Christina's choice of him becoming King, not to mention that the relationship between the crown and the nobility had already been strained during Christina's reign. However, Charles X was soon at war, when he invaded the Polish-Lithuanian Commonwealth in 1655. He may have invaded as John II Casimir of Poland still claimed the Swedish throne. Throughout the Second Northern Wars, other nations intervened, such as Denmark and Russia. In 1660 Charles XII fell ill and later died of an illness. As his son was young, a regency council took control of Sweden. They signed several peace treaties throughout the regency. The Treaty of Oliva (1660) saw John Casimir withdraw his claim to the Swedish throne. Despite,some losses it seemed that Sweden had benefited from the conflicts it had faced around this time. However, the regency council that followed Charles X's death made an alliance with France in April 1672 (Despite, Sweden being part of the Anti-French Triple Alliance of 1668, until it broke down in 1670).
Charles XI's reign was characterised by the Scanian War, which had come about due to the Swedish alliance with France, and his transformation of Sweden into a semi-absolute monarchy. He assumed full control of the monarchy during the Scanian War, as he thought the country needed a strong leadership throughout the war. However, when the Scanian War ended (the war had seen Sweden lose a lot of possessions, only to be regained through the treaties which ended the war) Charles XI was unwilling to give up the nearly absolute control he had over Sweden. Despite, this Charles XI's reign saw the longest period of peace for the Swedish Empire and reforms of the military, economy and government. After, the Scanian War, Charles XI kept Sweden out of foreign affairs and made into a neutral power. However, Charles died of stomach cancer in April 1697. In 1700 Sweden would once again find itself at war, as the Great Northern War began. Charles XII, son of Charles XI, would face a reign that was nearly all took up by war against an Anti-Swedish alliance.
Image Credit: http://www.slideshine.de/12660, Sébastien Bourdons