In 1835 Austria began pushing the Großdeutsche Lösung, or Greater German Decision, gaining political control over many lesser German states. Prussian and her remaining allies soon feared that Austria would declare war. On 1 January 1836 the War of German Hegemony began as Prussia invaded Austria. In 1837 the Treaty of Cologne was signed ending the war. The remainder of German states are loosely united under Prussian influence. Bohemia , Hanover, Schleswig-Holstein, the Electorate of Hesse, Frankfurt am Main, Nassau, and parts of Hesse-Darmstadt are annexed by Prussia The North German Confederacy is formed by Prussia, officially annexing parts of northern Germany. On 3 February the Second Congress of Vienna is called into order. The object of the congress was to discuss the future of a unif