Upon the conclusion of World War I, Germany suffered significant territorial losses from the Treaty of Versailles. After the German Revolution, the 21 constituent states of Germany abolished their monarchies and continued as republics alongside the three pre-existing city-states within the new Weimar Republic. The former Ernestine duchies continued briefly as republics before merging to form the state of Thuringia in 1920, except for Saxe-Coburg, which became part of Bavaria. Additionally, the Saar Basin and the city of Danzig were detached from Germany and placed in the care of the League of Nations.