Brandenburg was torn apart by a quarrel between the Protestants and the Catholics. When Gustavus Adolphus began his push into northern (Germany) in June–July 1630, he had just 4,000 troops. But he was soon able to consolidate the Protestant position in the north, using reinforcements from Sweden and money supplied by France at the Treaty of Bärwalde. Gustavus Adolphus was killed at the 1632 Battle of Lützen. Queen Maria Eleonora and the king's ministers took over the government of the Realm on behalf of Gustavus Adolphus' underage daughter Christina, until she reached the age of majority. Gustavus Adolphus is often regarded by military historians as one of the greatest military commanders of all time, with innovative use of combined arms.