World War I and the Weimar Republic

With the start of World War I in 1914, Italy withdrew from the Triple Alliance. Germany and Austria-Hungary, joined by Turkey and Bulgaria, formed the Central Powers, opposed eventually by 24 Allied Powers. The Allies gained victory in 1918 and the Treaty of Versailles stripped Germany of its colonies, its military might, and much of its industrial power. It lost Alsace-Lorraine, the Polish Corridor, and some border areas, including the Saar Basin. Germany agreed to pay war reparations.

With military defeat the monarchy collapsed, and a German Republic was proclaimed. A new constitution was prepared at Weimar and went into effect in August, 1919. Friedrich Ebert was elected President. After his death in 1925 he was succeeded by Field Marshal Paul von Hindenburg.The German people were bitterly resentful of the Versailles peace terms. Former military officers supported Adolf Hitler in his unsuccessful Munich revolt in 1923, which followed French occupation of the Ruhr.