 In the mid-20th century, some libertarian socialist groups emerged from disagreements with Trotskyism which presented itself as Leninist anti-Stalinism.As such, the French group Socialisme ou Barbarie emerged from the Trotskyist Fourth International, where Cornelius Castoriadis and Claude Lefort constituted a Chaulieu–Montal tendency in the French Parti Communiste Internationaliste in 1946.In 1948, they experienced their "final disenchantment with Trotskyism", leading them to break away to form Socialisme ou Barbarie, whose journal began appearing in March 1949.