American cinema's domination of world markets coincided with the rise of the Hollywood studios. The Hollywood Studio System would properly take hold by 1930 once five companies – Metro-Goldwyn-Mayer, RKO, Fox (later Twentieth-Century Fox), Warner Bros. and Paramount – had emerged victorious from increasing competition and a scrimmage of mergers and takeovers of production and distribution companies. By 1930 it is estimated that there were around 24,000 cinemas in the US with the five major studios controlling at least 50 per cent of the total industry output. By 1931, D. W. Griffith had made his last film and the film industry was primed to establish the classical Hollywood era with the new technology of sound. In fact, the era from the coming of the sound film to the end of the 1940s is often called Hollywood's ‘Golden Age’. During those years the Hollywood film factory fitted a Fordist model of capitalist mass production. In order to understand the success of the American film industry, it is important to examine the 1920s: the decade in which the studios employing thousands of people changed the face of Los Angeles and in which Thomas Ince's idea of the ‘factory system’ of production took hold.