But he said the Vatican nevertheless exerted influence regarding his filming permits, and he was told it would not be possible even to shoot scenes in Rome that had churches in the background.

"When you come to film in Rome, the official statement to you is that the Vatican has no influence," he said. "Everything progressed very smoothly, but unofficially a couple of days before we were to start filming in several of our locations, it was explained to us that through back channels and so forth that the Vatican had exerted some influence."

"Was I surprised? No. Am I a little frustrated at times? Sure," he said.

Nevertheless he said he felt that he was able to preserve the overall "Angels & Demons" experience despite the restrictions by recreating scenes on sets. For the Sistine Chapel alone, some 20 members of the production crew — posing as tourists — took photos of all the frescoes, floor mosaics and paintings of the tiny chapel where popes are elected — until they were told to stop, the film's Web site says.