History of Germany during World War I
In November 1918, with internal revolution, a stalemated war, Bulgaria and the Ottoman Empire suing for peace, Austria-Hungary falling apart from multiple ethnic tensions, and pressure from the German high command, the Kaiser and all German ruling princes abdicated. On 9 November 1918, the Social Democrat Philipp Scheidemann proclaimed a Republic, in cooperation with the business and middle classes, not the revolting workers. The new government led by the German Social Democrats called for and received an armistice on 11 November 1918; in practice it was a surrender, and the Allies kept up the food blockade to guarantee an upper hand. The war was over; the history books closed on the German Empire. It was succeeded by the democratic, yet flawed, Weimar Republic.
Anschluss
The idea of grouping all Germans into one nation-state had been the subject of debate in the 19th century from the dissolution of the Holy Roman Empire in 1806 until the break-up of the German Confederation in 1866. Austria had wanted a "Großdeutsche Lösung" (greater Germany solution), whereby the German states would unite under the leadership of the German Austrians (Habsburgs). This solution would have included all the German states (including the non-German regions of Austria), but Prussia would have had to take second place. This controversy, called dualism, dominated Prusso-Austrian diplomacy and the politics of the German states in the mid-nineteenth century.