a German revolutionary socialist group founded in 1916 by Rosa Luxemburg and Karl Liebknecht (1871–1919). At the end of 1918 the group became the German Communist Party, which in 1919 organized an uprising in Berlin that was brutally crushed.
Spartacus was adopted as a pseudonym by Karl Liebknecht
Spartacus League in other Oxford dictionaries
Definition of Spartacus League in the US English dictionary