In the wake of the 1917 October Revolution and the First World War, when the Third (Communist) International got off the ground, the socialist movement underwent its first major split since becoming a mass movement in the last decades of the nineteenth century. The second significant rupture occurred about forty years later, affecting both Second International socialism and Third International communism. In the mid- to late 1950s, an international New Left suddenly emerged that captured the attention and imagination of several generations of activists, though it never came to the founding of a new international association that could have given added structure to the heterogenous forces of this New or Radical Left, which dissipated as an internationally relevant force in the course of the 1970s and 1980s.