When Dan Brown's defining novel The Da Vinci Code was released, it caused an uproar: many Christians complained it was an unfair attack on the Catholic Church, conspiracy theorists smugly announced they'd told us all so, and people started hunting yet again for the Holy Grail. The film attracted similar controversy, with protests held during filming and outside cinemas. Whether or not these reactions were justified, director Ron Howard may want to prepare for another round of controversy with this month's release of Angels & Demons, the sequel to the 2006 blockbuster. The novel on which this second instalment is based was actually a prequel to The Da Vinci Code book. But in the movie, the lead character, symbologist Robert Langdon, has already upset the Vatican by trying to find the Holy Grail, and yet the holy city calls on him to help save the Church from the actions of a secret brotherhood known as the Illuminati. 'Langdon enters into Angels & Demons with an icy relationship vis-?-vis the Vatican because of the events of The Da Vinci Code,' says actor Tom Hanks, who plays Professor Langdon. 'He has a great knowledge, obviously, of the organisation of the church and its rituals and history but he is not necessarily a welcome person. Essentially, there is a grab for power at the Vatican in the guise of the hijacking of the papal election and, in spite of his history with the church, the right man gets the job to prevent that.' Despite the potential for controversy, a month was spent filming in Rome, which surrounds the Vatican, as the city's landmarks serve as crucial clues to the Illuminati's plot to destroy the Catholic Church and the Vatican itself. Filming in the summer meant the city's streets were filled with tourists, but this didn't bother cinematographer Salvatore Totino. 'All the tourists in Rome provided a bit of fun pandemonium and in a way that worked well with our approach. Ron and I talked about giving the film a sense of urgency - there's a bomb that is going to go off in the Vatican if they don't stop it, so the goal was to convey that high-stakes deadline cinematically.' Whatever you feel about the historical and religious aspects of Brown's stories, it's hard to deny they are a great starting point for fast-paced, mystery-packed cinematic romps. 'What's so great about a Robert Langdon adventure is that it stimulates so much curiosity and research,' Howard says. 'Whether you believe it or not, it's fascinating stuff, and in Dan Brown's fertile imagination, it leads to a spellbinding set of clues and a great mystery.'