Karl Liebknecht, German politician, co-founded Communist Party of Germany (died 1919)

Karl Paul August Friedrich Liebknecht was a German politician and revolutionary socialist. A leader of the far-left wing of the Social Democratic Party of Germany (SPD), Liebknecht was a co-founder of both the Spartacus League and Communist Party of Germany (KPD) along with Rosa Luxemburg.

The Communist Party of Germany was the major far-left political party in the Weimar Republic during the interwar period, an underground resistance movement in Nazi Germany, and a minor party in Allied-occupied Germany and West Germany during the post-war period until it merged with the SPD in the Soviet occupation zone in 1946 and was banned by the West German Federal Constitutional Court in 1956.

August 13 is the 225th day of the year in the Gregorian calendar; 140 days remain until the end of the year.