Gustavus Adolphus, known as the 'Lion of the North,' was the King of Sweden from 1611 until his death in 1632. He is celebrated for his military innovations and leadership during the Thirty Years' War, where he played a crucial role in the Protestant cause against the Catholic Habsburgs. His strategies transformed the Swedish army into one of the most effective fighting forces of the time, emphasizing mobility and firepower. Gustavus Adolphus's legacy includes not only his military achievements but also his contributions to the development of modern warfare and the establishment of Sweden as a major European power.