Title: History of Sweden (1611–48)
Content: resulting from this commanding position was of material assistance during the earlier stages of the war in Germany, whither Gustavus transferred his forces in June 1630. Gustavus, later to be called "the Lion of the North" due to his skills as a commander, intervened on the Protestant side in the German civil war. Using new military techniques such as lighter and more mobile artillery and cavalry shocks, he won an astounding victory at the Battle of Breitenfeld in 1631. In the Battle of Lützen on November 6, 1632, he was killed, though, and Sweden lost their warrior-king. The battle itself

Title: Military history of Sweden
Content: "the Lion of the North" due to his skills as a commander, intervened on the Protestant side in the German civil war. Using new military techniques such as lighter and more mobile artillery, a larger proportion of his infantry using firearms (as opposed to pikes), and cavalry shock tactics, he won a crushing victory at the Battle of Breitenfeld in 1631. In the Battle of Lützen on November 6, 1632, he rode into a group of enemy cavalry and was killed. The battle itself was a draw. Two years later Imperial troops won a convincing victory over the Protestant Army

Title: House of Vasa
Content: a short-lived Polish–Swedish union, was usurped in 1599 by John's Protestant brother King Charles IX of Sweden in the War against Sigismund. The dynasty was split into a Protestant Swedish branch and a Catholic Polish one, which contended for crowns in subsequent wars. The involvement of the famous Protestant general and King Gustavus Adolphus of Sweden in the Thirty Years' War gave rise to the saying that he was the incarnation of "the Lion of the North" (German: "Der Löwe von Mitternacht"). Yet, notably, his daughter and heiress Queen Christina of Sweden (1632–1654) abdicated in 1654 after converting to Catholicism,

Title: House of Vasa
Content: other countries, which had been conquered for Lutheranism, to be reconquered for Catholicism (via the Counter-Reformation). His involvement in the Thirty Years' War gave rise to the saying that he was the incarnation of "the Lion of the North", or as it is put in German "der Löwe von Mitternacht". Gustav II Adolf's success in making Sweden one of the great powers of Europe, and perhaps the most important power in the Thirty Years' War after France and Spain, was due not only to his military brilliance, but also to important institutional reforms in Sweden's government. The chief among these

Title: Gustavus Adolphus of Sweden
Content: and chose the Prussian city of Elbing as the base for his operations in Germany. He died in the Battle of Lützen in 1632. His early death was a great loss to the Lutheran side. This resulted in large parts of Germany and other countries, which had been conquered for Lutheranism, to be reconquered for Catholicism (via the Counter-Reformation). His involvement in the Thirty Years' War gave rise to the saying that he was the incarnation of "the Lion of the North", or as he is called in German "Der Löwe aus Mitternacht" ("Literally: "The Lion of Midnight""). Historian Ronald

Question: Which 17th-century king of Sweden was known as the "Lion of the North"?
Answer: Gustavus Adolphus