Complex sentence: There were many famous people who performed at the opera house including Harry Houdini, Amelia Earhart, Lionel Barrymore, John L. Sullivan who did a showing of Uncle Toms Cabin and the film producer G.W Griffith who showed his movies "Birth of The Nation".
Split into simpler sentences: There were many famous people who performed at the opera house. Including Harry Houdini, Amelia Earhart, Lionel Barrymore, John L. Sullivan who did a showing of Uncle Toms Cabin and the film producer G.W Griffith who showed his movies "Birth of The Nation".