Charles XII of Sweden
He left the country three years later to embark on a series of campaigns overseas. These battles were part of the Great Northern War, fought against Russia, Saxony and Denmark-Norway, countries that had joined in a coalition to attack Sweden.
Charles XII was a skilled military leader and tactician. However, although he was also skilled as a politician, he was reluctant in making peace. Charles is quoted by Voltaire as saying upon the outbreak of the Great Northern War, "I have resolved never to start an unjust war but never to end a legitimate one except by defeating my enemies." Although Sweden achieved several large scale military successes early on, and won the most battles, the Great Northern War eventually ended in Sweden's defeat and the end of the Swedish Empire.
The fact that Charles was crowned as Charles XII does not mean that he was the 12th king of Sweden by that name. Swedish kings Erik XIV (1560–1568) and Charles IX (1604–1611) gave themselves numerals after studying a mythological history of Sweden. He was actually the 6th King Charles. The non-mathematic numbering tradition continues with the current King of Sweden, Carl XVI Gustaf, being counted as the equivalent of Charles XVI.