The Freikorps were paramilitary units formed in Germany after World War I, primarily composed of World War I veterans. They emerged in 1918 and played a significant role in suppressing leftist uprisings, particularly during the German Revolution and the Spartacist Uprising in 1919. These groups were often nationalist and anti-communist, reflecting the political turmoil of the Weimar Republic. The Freikorps were known for their brutal tactics and were instrumental in shaping the political landscape of post-war Germany, influencing the rise of extremist movements, including the Nazi Party.