The German Confederation was a loose association of 39 German states in Central Europe, created by the Congress of Vienna in 1815 to coordinate the economies of separate German-speaking countries and to replace the former Holy Roman Empire. According to historian Lloyd E. Lee, most historians have judged the Confederation to be weak and ineffective, as well as an obstacle to German nationalist aspirations. It collapsed due to the rivalry between Prussia and Austria, warfare, the 1848 revolution, and the inability of the multiple members to compromise. It dissolved after the Prussian victory in the Seven Weeks' War and the establishment of the North German Confederation in 1866.