Gustavus Adolphus, also known in English as Gustav II Adolf or Gustav II Adolph, was King of Sweden from 1611 to 1632, and is credited for the rise of Sweden as a great European power. During his reign, Sweden became one of the primary military forces in Europe during the Thirty Years' War, helping to determine the political and religious balance of power in Europe. He was formally and posthumously given the name Gustavus Adolphus the Great by the Riksdag of the Estates in 1634.
He is often regarded as one of the greatest military commanders in modern history, with use of an early form of combined arms. His most notable military victory was the Battle of Breitenfeld. With his resources, logistics, and support, Gustavus Adolphus was positioned to become a major European leader, but he was killed a year later at the Battle of Lützen. He was assisted in his efforts by Count Axel Oxenstierna, the Lord High Chancellor of Sweden, who also acted as regent after his death.