The thesis examines the reasons why the German National Assembly of 1919 chose proportional representation to elect officials to the German Reichstag. Sources include the series Quellen zur Geschichte des Parlamentarismus and die politische Parteien, the "Hajo Holborn Papers", and the Reich Ministry of Interior debates concerning the institutional draft. The thesis traces the arguments for proportional representation, its use throughout Europe before 1914, and voting reform in Germany during World War I. The thesis surveys the German provisional government's adoption of proportional representation, emphasizing the constitutional drafts of Hugo Preuss and the role of the provisional government. Finally, the thesis scrutinizes the National Assembly debates, concluding that most of its members had already decided to follow the provisional government's course and accept proportional representation.