The Weimar Republic (still called the Deutsches Reich, or German Empire, during its existence), was formed in 1919 after the German Revolution of 1918, the direct result of the German Empire's defeat in the Great War.
The period of the Weimar Republic has become synonymous with hyperinflation and the rise of political extremism. The cost of the War, the reparations demanded of the allies and the need to develop its infrastructure resulted in hyperinflation. French forces even overran the Ruhr when they were not satisfied they were getting their just funds. The Dawes Plan reduced the original reparation figure that eased the pressure and the Reichsbank issued a stabilising currency, the Rentenbank, which stopped the hyperinflation.
The misery and poverty of the post war period, together with the humiliation of defeat, contributed to the rise of extremist parties and ultimately the rise to power of the National Socialist German Workers', or Nazi, Party.