Sweden held, for a time, control of the principal trade routes of the Baltic; and the increment of revenue resulting from this commanding position was of material assistance during the earlier stages of the war in Germany, whither the Swedish king Gustavus II Adolphus 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, 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 at Nördlingen. In order to prevent the Habsburg's from winning the war, France, who had already given major financial subsidies to Sweden, intervened on the Protestant side. The war dragged on for many years until a peace agreement was at last reached in 1648. In the Peace of Westphalia Sweden received an indemnity, as well as control of Western Pomerania and the bishoprics of Bremen and Verden. It thus won control of the mouth of the Oder, Elbe, and Weser Rivers, and acquired three voices in the Council of Princes of the German Reichstag.