The studio's executive producer, Darryl F. Zanuck, resigned during a contract dispute with Harry Warner in 1933. According to a 1933 letter that Jack wrote to Will H. Hays, then president of the Motion Picture Producers and Distributors of America, Zanuck requested a higher salary and "indicated his desire to raise the salaries of the actors and personnel in the motion pictures we were producing". That year, Zanuck established Twentieth Century Pictures, which merged with Fox Film Corporation in 1935. Longtime producer for the studio, Hal B. Wallis, took over as the studio's executive producer. Warner, however, denied Wallis the sweeping powers enjoyed by Zanuck, and the result was a decentralization of creative and administrative control that often created confusion at the studio. Under the new system, each picture was assigned a supervisor who was usually plucked from the ranks of the studio's screenwriters. Although Warner Bros. maintained a high rate of production throughout the 1930s, some pictures showed an uneven quality that reflected "not only the difficulty of shifting to a supervisory system but also the consequences of dispersing authority into the creative ranks".