Luxemburg co-founded the Spartacus League on March 31, 1916.
From her prison cell on March 31, 1916, Rosa Luxemburg co-founded the Spartacus League with Karl Liebknecht, independent of the German Social Democratic Party. The group emerged as a leading voice against World War I, advocating for class struggle over national interests. The league's anti-war stance laid the groundwork for revolutionary activities in Germany, culminating in the formation of the Communist Party of Germany. Despite her incarceration, Luxemburg's influence on the league was profound, emphasizing grassroots mobilization and direct action.