The Conjuring" tells the true story of Ed and Lorraine Warren (Patrick Wilson, Vera Farmiga), world renowned paranormal investigators, who were called to help a family terrorized by a dark presence in a secluded farmhouse. Forced to confront a powerful demonic entity, the Warrens find themselves caught in the most horrifying case of their lives.The pursuit of creating a film adaptation of the events on the Perron family farm began over 20 years ago when Ed Warren played producer Tony DeRosa-Grund the tape of the original interview Warren had with Carolyn Perron when he had visited the farmhouse for the first time. DeRosa-Grund recorded Warren playing back the tape from his original investigation of the case. It was Warren's original interview with the Perron family who were under demonic attack. At the end of the tape Warren can be heard saying to DeRosa-Grund, "If we can't make this into a film I don't know what we can." On the recording, DeRosa-Grund can be heard laying out his version of the movie for Ed.DeRosa-Grund went on to write the original treatment and titled the project The Conjuring. For nearly 14 years, he tried to get the movie made without any success. Finally he landed a deal to make the movie at Gold Circle Films, the production company behind The Haunting in Connecticut, but no terms were agreed on and the deal was dropped.After DeRosa-Grund aligned with producer Peter Safran, sibling writers Chad and Carey Hayes were brought on board to refine the script. Using DeRosa-Grund's treatment, as well as his Ed Warren tape, the Hayes brothers changed the story's point of view from the Perron family to the Warrens. At the very beginning of the writing process, the brothers began interviewing Lorraine Warren many times over the phone to straighten up details. By mid-2009, the property became the subject of a six-studio bidding war that initially resulted in the film landing at Summit Entertainment. However, after DeRosa-Grund and Summit couldn't conclude the transaction and the film went into turnaround. DeRosa-Grund then reconnected with New Line Cinema, who ultimately picked up the film after losing out in the original bidding. On November 11, 2009, an official deal was made between New Line and DeRosa-Grund's Evergreen Media Group.
Warner Bros. initially intended to release the film early 2013, but decided on a summer release date after gaining a positive reception from test audiences. Because of this, it is one of the first horror films to receive a wide release during the months of June or July since 2006's The Omen. A trailer and a clip from the film was shown at the 2012 New York Comic Con. In March 2013, the film was given an R-rating by the MPAA for being what Wan described as "too adult." "When we sent it , they gave us the R-rating," said executive producer Walter Hamada. "When we asked them why, they basically said, 'It's just so scary. There are no specific scenes or tone you could take out to get it PG-13.'"The world premiere took place June 6, 2013, at the closing night of the first edition of Nocturna: Madrid International Fantastic Film Festival. This was followed by two screenings of the film at the Los Angeles Film Festival on June 21 that also featured a Q&A segment with director James Wan.