De Sade is the biography of Donatien Alphonse Francois, the Marquis de Sade, told as he hides from police in an abandoned ancestral estate. The Marquis (Keir Dullea) was a French aristocrat, politician, philosopher and writer who became famous for his revolutionary literature and infamous, in some circles, for erotic works that combined philosophical discourse with sexual fantasies, violence and blasphemy against the Catholic Church. He was imprisoned for nearly one-third of his life. Set in the early 1800s, the film introduces an aging Marquis and uses psychedelic and erotic imagery (the film's nudity and sexual content was notorious when released in 1969) to recall his life of debauchery from childhood to manhood. A complex structure leaves viewers to figure out if they are watching the major incidents of the Marquis' life through his own fantasies and memories, or if they are theatrical performances staged by his wicked uncle, Abbe de Sade (John Houston).