Róża Luksemburg (5 March 1871 – 15 January 1919) was a Polish and naturalised-German Marxist theorist and revolutionary. She was a leading theorist of the Social Democratic Party of Germany (SPD) and later co-founded the anti-war Spartacus League, which evolved into the Communist Party of Germany (KPD). An influential member of the international socialist movement, she is remembered for her writings on imperialism and revolution, and as a champion of socialist democracy.