Fabianism, socialist movement and theory that emerged from the activities of the Fabian Society, which was founded in London in 1884. (Read George Bernard Shaw’s 1926 Britannica essay on socialism.) Fabianism became prominent in British socialist theory in the 1880s. The name Fabian derives from Quintus Fabius Maximus Verrucosus, the Roman general famous for his delaying tactics against.