With the German Revolution of 1918–1919 and the fall of the Hohenzollern monarchy resulting from World War I, the Prussian House of Lords was dissolved by the government of Minister President Paul Hirsch. According to the 1920 constitution of the Free State of Prussia it was replaced by the Staatsrat (state council) of representatives delegated by the Landtag assemblies of the Provinces. The Cologne mayor Konrad Adenauer served as president of the state council from 1921 until the Nazi Machtergreifung in 1933.