The studio system quickly became so powerful that some filmmakers once again sought independence. On February 5, 1919 four of the leading figures in American silent cinema (Mary Pickford, Charles Chaplin, Douglas Fairbanks, and D. W. Griffith) formed United Artists, the first independent studio in America. Each held a 20% stake, with the remaining 20% held by lawyer William Gibbs McAdoo. The idea for the venture originated with Fairbanks, Chaplin, Pickford, and cowboy star William S. Hart a year earlier as they were traveling around the U.S. selling Liberty bonds to help the World War I effort. Already veterans of Hollywood, the four film stars began to talk of forming their own company to better control their own work as well as their futures. They were spurred on by the actions of established Hollywood producers and distributors, who were making moves to tighten their control over their stars' salaries and creative license. With the addition of Griffith, planning began, but Hart bowed out before things had formalized. When he heard about their scheme, Richard A. Rowland, head of Metro Pictures, is said to have observed, "The inmates are taking over the asylum."