Rosa Luxemburg (also Rozalia Luxenburg; ; 5 March 1871 – 15 January 1919) was a Marxist theorist, philosopher, economist and revolutionary socialist of Polish-Jewish descent who became a naturalized German citizen. She was, successively, a member of the Social Democracy of the Kingdom of Poland and Lithuania (SDKPiL), the Social Democratic Party of Germany (SPD), the Independent Social Democratic Party (USPD), and the Communist Party of Germany (KPD).