Karl XII, nicknamed the “Madman of the North”, had a reign that was marked by continual warfare against Poland, Denmark, and Russia, in what is known as the Great Northern War. Eventually, he was defeated by Russia, marking the end of Sweden’s era as a great power. Karl XIl’s death during the siege of Fredrikshald remains a point of contention. There are various theories about who was responsible for his death – a Norwegian soldier, a Swedish soldier tired of war, or even an agent of his brother-in-law, Frederick, who later became Frederick I of Sweden. One of the more bizarre theories suggests that he was killed with a button, based on rumours that he was impervious to bullets.