After Austerlitz, Napoleon established the Confederation of the Rhine in 1806. A collection of German states intended to serve as a buffer zone between France and Central Europe, the creation of the Confederation spelled the end of the Holy Roman Empire and significantly alarmed the Prussians. The brazen reorganization of German territory by the French risked threatening Prussian influence in the region, if not eliminating it outright. War fever in Berlin rose steadily throughout the summer of 1806. At the insistence of his court, especially his wife Queen Louise, Frederick William III decided to challenge the French domination of Central Europe by going to war.

What is the name of the political body composed of German states established by Napoleon in 1806?