German Empire
The high command under Paul von Hindenburg and Erich Ludendorff increasingly controlled the country, but in October after the failed offensive in spring 1918, the German armies were in retreat, allies Austria-Hungary and the Ottoman Empire had collapsed, and Bulgaria had surrendered. The Empire collapsed in the November 1918 Revolution with the abdications of its monarchs. This left a postwar federal republic and a devastated and unsatisfied populace, which later led to the rise of Adolf Hitler and Nazism.
Allied-occupied Germany
Upon the defeat of Nazi Germany in World War II, the victorious Allies asserted their joint authority and sovereignty over 'Germany as a whole', defined as all territories of the former German Reich which lay west of the Oder–Neisse line, having declared the destruction of Nazi Germany at the death of Adolf Hitler (see 1945 Berlin Declaration). The four powers divided 'Germany as a whole' into four occupation zones for administrative purposes, under the United States, United Kingdom, France and the Soviet Union respectively; creating what became collectively known as Allied-occupied Germany (). This division was ratified at the Potsdam Conference (17 July to 2 August 1945). The four zones were as agreed in February 1945 by the United States, United Kingdom and Soviet Union meeting at the Yalta Conference; setting aside an earlier division into three zones (excluding France) proposed by the London Protocol.