charles xii of sweden
Also known as Carolus Rex, Charles XII (June 17, 1682 - November 30, 1718) was last king of the Swedish Empire before its downfall in the Great Northern War.
He was crowned at age 15 on the 14th of December, 1697, and ruled from April 5th, 1697 until his death on November 30th, 1718 (age 36), after which his body was carried back from Norway to Sweden by soldiers to be buried in Stockholm.
During his reign, he launched a series of military campaigns to strengthen Sweden's control over the Baltic and as a major European power, including a disastrous invasion of Russia that eventually lead to the empire's collapse.