Complex sentence: In addition to her work as an artist, Markham was an accomplished actress, performing with the Chicago Little Theater from 1909 to the 1920s and with the Provincetown Players from 1916, and appearing in movies in Los Angeles.
Split into simpler sentences: In addition to her work as an artist, Markham was an accomplished actress. She appeared with the Chicago Little Theater from 1909 to the 1920s, with the Provincetown Players from 1916, and in movies in Los Angeles.