Karl Liebknecht (help·info) (August 13, 1871 - January 15, 1919) was a German socialist and a co-founder of the Spartacist League and the Communist Party of Germany.

On December 31, 1918 / January 1, 1919, he was involved in the founding of the KPD. Together with Rosa Luxemburg, Leo Jogiches and Clara Zetkin, Liebknecht was also instrumental in the January 1919 Spartacist uprising in Berlin. The uprising was brutally opposed by the new German government under Friedrich Ebert with the help of the remnants of the Imperial German Army and freelance right-wing militias called the Freikorps; by January 13, the uprising had been extinguished. Liebknecht and Rosa Luxemburg were abducted by Freikorps soldiers on January 15, 1919, and brought to the Eden Hotel in Berlin where they were tortured and interrogated for several hours. Following this, Luxemburg was battered to death with rifle butts and thrown into a nearby river while Liebknecht was shot in the back of the head then deposited as an unknown body in a nearby mortuary.