This 1971 film is based on a book called 'The Devils of Loudon' by Aldous Huxley. Both film and book are derived from some strange events that took place in a convent in 17th century France.

The film follows the fortunes of a priest, Urbain Grandier, and the Mother Superior of the Loudon convent, who according to the film is in love with him. Grandier, played by Olliver Reed, secretly (and illegally) marries a young girl, while the Mother Superior (Vanessa Redgrave) encourages an atmosphere of hysteria which eventually leads to most of the nuns in her care seeming to go insane. This is put down to demonic possession and the Inquisition is called in.

As far-fetched as the events in the film seem, they have a factual basis. It seems likely that politics played a big role in what happened; some figures in the local church wanted to get rid of Grandier, and some of the nuns may have been encouraged to 'act mad' so he could be accused of practising witchcraft on them.

The film suffered from censorship and heavy cutting due to its sexual and violent scenes, but it's now regarded as one of Russell's best.