Wilhelm Martin Philipp Christian Ludwig Liebknecht (29 March 1826 – 7 August 1900) was a German socialist and one of the principal founders of the Social Democratic Party of Germany (SPD). His political career was a pioneering project combining Marxist revolutionary theory with practical legal political activity. Under his leadership, the SPD grew from a tiny sect to become Germany's largest political party. He was the father of Karl Liebknecht and Theodor Liebknecht.
威廉·李卜克内西