During the Thirty Years' War, Sweden conquered approximately half of the Holy Roman states. Gustav Adolphus planned to become the new Holy Roman Emperor, ruling over a united Scandinavia and the Holy Roman states, but he died at the Battle of Lützen in 1632. After the Battle of Nördlingen, Sweden's only significant military defeat of the war, pro-Swedish sentiment among the German states faded. These German provinces excluded themselves from Swedish power one by one, leaving Sweden with only a few northern German territories: Swedish Pomerania, Bremen-Verden and Wismar. The Swedish armies may have destroyed up to 2,000 castles, 18,000 villages and 1,500 towns in Germany, one-third of all German towns.