Church leaders around the world urged their members to boycott the book and film version of "The Da Vinci Code," and protestors showed up outside some early screenings of the film. The film was also bitterly contested by the conservative Roman Catholic organization Opus Dei, which was represented in the film by a ruthless killer monk.
Brown declined to comment on the ban by the Diocese. But the president of the Catholic League, Bill Donohue, was supportive of the decision.
In a statement on the League's Web site, he wrote, "We are delighted that Ron Howard and his Hollywood minions have been denied the opportunity to exploit the Catholic Church again. Any movie about Catholicism which draws on the specious work of Dan Brown is bound to offend Catholic sensibilities, so it was only fitting that Howard was shown the gate."
Donohue told ABCNews.com that, although "Angels and Demons" does not appear to be as "demonizing" of the Catholic Church as "The Da Vinci Code," he is concerned about the way in which Brown mixes fact and fiction in his novels.
"It's this pernicious intertwining," he said. "I'm questioning what he regards as being factual."
But Donohue does not believe that this movie will draw the same ire that its predecessor did, because it does not tackle big theological questions.
"There's a concern any time you have a movie adaptation of a Dan Brown novel," he said. "But I believe the decibel level will be somewhat less."
Howard, who also directed "The Da Vinci Code," started shooting earlier this month in Rome, after the production was delayed by the Writers Guild of America strike, which ended in February.
According to the Ansa news agency, Howard will shoot outside the two churches -- where permission to film is granted solely by the city of Rome -- before recreating the interiors in a Hollywood studio later this year. With filming inside the Vatican out of the question, the filming of a scene at the Vatican staircase will now be shot in a grand villa south of Rome in Caserta.
"I'm sure it's not going to disturb Ron Howard or Dan Brown," Donohue said. "But now they'll have to drop a dime to find some other churches to rip off."