Claim: Swedish Empire was ruled by Gustav II Adolf for 21 years.
Evidence: The beginning of the Empire is usually taken as the reign of Gustavus Adolphus , who ascended the throne in 1611 , and the end as the loss of territories in 1721 following the Great Northern War.
Gustav II Adolf -LRB- 9 December 1594 -- 6 November 1632 , O.S. -RRB- ; widely known in English by his Latinised name Gustavus Adolphus or as Gustav II Adolph , was the King of Sweden from 1611 to 1632 and is credited as the founder of Sweden as a Great Power -LRB- Stormaktstiden -RRB-.
In an era characterized by almost endless warfare , he led his armies as king from 1611 -LRB- at age 16 -RRB- until his death in battle in 1632 while leading a charge.