In 1813, Prussia again started war with Napoleonic France. In 1815, Prussia won back the land it lost in earlier wars and also all the Rhineland and Westphalia and some other land. This land in the west was very important, especially the Ruhr valley. It was the new center of Germany's industrialization and the home of the weapons industry. After the Napoleonic Wars, Prussia was the strongest power in Germany and more powerful than Austria. 