Christy Cabanne, who had helped her on her first day as an extra. He was excited to have found her as Griffith had been looking for her but since she did not have a telephone number they had been unable to find her. Her first day back at Biograph, Griffith called her into his office five times, but sent her away each time. The final time he asked her to rehearse a scene with Bobby Harron, telling her Bobby was playing her sweetheart, a confederate soldier going off to war. Pleased with what he'd seen, Griffith told her they would leave for California, where he would make a picture about the Civil War. She would make $35 a week. Cooper began work on several pictures for Reliance Majestic, which were made under Griffith's supervision, and began preparations for The Birth of a Nation. She stated she didn't remember being in several films as she was never told which scenes she played ended up in which picture. During this time she acted in one of Griffith's first attempts at a feature, Home, Sweet Home (1914), although she also didn't remember anything about that film. After working several months for the company, Cooper's star was rising and she was given a star dressing room with Mae Marsh. She couldn't recall the start of The Birth of a Nation other than Griffith announced he was making his Civil War picture, and they still did not use scripts. Cooper was given one of the leading roles as the eldest Southern daughter Margaret Cameron. As was standard at the time, Cooper did her own makeup and hair. Cooper lived the role and found her only truly difficult scene came acting opposite Henry B. Walthall, whom she found cold and difficult. After having troubles in rehearsal with the scene, she also had trouble while filming. To get her to act upset in the scene Griffith took her aside and told her that her mother had died. Despite the trick, Cooper was never angry with him for it. Cooper's sister Lenore visited her while filming and ended up as an extra playing Lillian Gish's maid in blackface. While having trouble funding the film, Griffith offered Cooper a chance to invest in it, but Cooper had no money. Had she invested, Cooper would have made thousands back. Cooper was too ill to see the picture when it premiered