Fact-checking 'Conclave': How accurate is the pope movie based on the book?

We're discussing the voting process depicted in the new papal thriller "Conclave" (in theaters now). Light spoilers ahead!

Twice in past years, I hopped a flight to Rome in order to cover one of the most arcane, storied and secretive events in human history: the election of a new pope.

That event is also known as a conclave, a term that lends its name to a 2016 Robert Harris book turned movie thriller. "Conclave" is set during a fictional meeting of red-cloaked cardinals who have flocked to the Eternal City to cast ballots for who will lead the world's roughly 1.4 billion Catholics.

Many are familiar with the final moments of a conclave, when the white smoke famously rises from a chimney just outside the Sistine Chapel, sending the assembled faithful into a frenzy of cheers, followed by the appearance of the newly elected pontiff on the central balcony at St. Peter's Basilica.

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But given that the Vatican doesn't really do Hollywood, one wonders how the filmmakers were able to capture the nuanced details ? from elaborate clothing to Latinate voting oaths ? shown in the movie, which stars Ralph Fiennes, Stanley Tucci and John Lithgow as at-odds cardinals, and Isabella Rossellini as an inquisitive nun.

"We were given a private tour of the Vatican, and they were quite welcoming, actually, quite helpful," says "Conclave" screenwriter Peter Straughan. "So it was a big research project, really. It's a fascinating and theatrical world, so you want to get those details right. It's a very sumptuous thing."

Vatican officials seemed OK with the shocking premise of the film, Straughan adds, as well as its portrayal of a conclave's political machinations. "We didn't want to be toothless in our approach to the church, which has many faults, but we wanted to be respectful of the heart of the Catholic Church," he says.

Straughan guides USA TODAY through the questions that surface when watching "Conclave."

How much of 'Conclave' was actually filmed at the Vatican?

None. "You can't film at the Vatican, ever," says Straughan. "We had to come up with alternatives."

Most of those alternatives were in fact in Rome, which is packed with marble-encrusted buildings from centuries past that can double for many of the chambers, staircases and hallways featured in "Conclave." (One notable exception: The instantly recognizable interiors of the Sistine Chapel were re-created on a soundstage, and Michelangelo's famous ceiling is a computer-generated replica of the real thing.)

Do the 235 Roman Catholic cardinals really get sequestered like juries until they choose a pope?

Yes. As shown in "Conclave," once a Vatican official faces the assembled cardinals and says the words "extra omnes" (or "everyone out") the cardinals are allowed to interact only with each other. "There isn't supposed to be any information coming in from the outside world, or going out, that could sway the election in any way," Straughan says.

There are, however, some officials who as needed can act as emissaries, even if the cardinals themselves cannot leave until a successful ballot is cast, meaning one cardinal receives two-thirds of the votes and is elected pope. "While some people can go back and forth, I'm not sure they're used as detectives as they are in our story," Straughan says.

Do cardinals who gather for a conclave sleep on the premises?

The cardinals stay at the Casa Santa Marta, a fairly simple dormitory on Vatican grounds. They are allowed to mix and mingle in nearby buildings and courtyards, and dine together in a cafeteria setting staffed by nuns.

"Visually you get this strange mix of absolute ancient beauty and tremendous scale, contrasting with this almost business conference center feel," Straughan says. "You get this major stage feel, with the Sistine Chapel and these men deciding who will represent the world's Catholics, and then this almost modest backstage feel. Quite the contrast, which makes for a great setting."

Is the voting process in a papal conclave as formal as shown in 'Conclave'?

When cardinals assemble to elect a pope, they vote as often as four times a day, especially in the first day or two, to determine which candidates are most likely to garner a majority vote. As shown in "Conclave," the balloting process is not a raucous affair but solemn and filled with ritual. "Each time each cardinal votes, he must walk up to the bowl where his written vote will be placed and recite an oath (in Latin)," Straughan says.

One by one, the cardinals place their folded ballots atop a round plate and slide it into an oval urn while reciting an oath. As "Conclave" shows, those ballots are sewn together with a needle and thread, and then burned with a chemical to send either black smoke, meaning a stalemate, or white, signifying "habemus papam" ? "we have a pope."

This article originally appeared on USA TODAY: Is 'Conclave' a true story? We fact check the book turned movie