FACT: In 1495, Leonardo da Vinci began work on one of his most famous pieces, “The Last Supper,” a fresco in the refectory of the Santa Maria delle Grazie in Milan. The painting measures 13 feet, 9 inches high and 29 feet, 10 inches long. In 1943, Allied forces bombed most of the building, leaving it in ruins. The painting, however, survived.

A new sort of secret society is being created. It occupies the nooks of libraries, coffee shops and the friendly conversation of book clubs in comfy overstuffed chairs.

The secret password to get in goes like this:

Person 1: Have you read the book?

Person 2: Yes.

Person 1: What did you think?

Knowing smiles pass between the two. Access granted.

More than 6.5 million copies of Dan Brown’s “The Da Vinci Code” have been sold, bringing together a new society of people who delight in the adventures of the character of Robert Langdon, Harvard’s dashing professor of religious symbology. Brown leads readers through a whirlwind maze of codes and hidden symbols, revealing the ancient meaning of Leonardo da Vinci’s “The Last Supper,” the real truth about the Holy Grail and the conspiracy of the Roman Catholic Church against the pagan values of balance between male and female.

Some say the book has revived religious conversation and created new interest in art history. Others see it as historically misleading.

In a book touted for its historical facts and research, local experts say there seem to be some glaring inaccuracies. Which leads to the question: Where does fact end and fiction begin, and how does the public discern between the two?

FACT: The literal translation of the name “Leonardo da Vinci” from Italian to English is “Leonardo from Vinci.” Leonardo was born on April 15, 1452, near the town of Vinci, Italy. Contrary to popular belief, da Vinci is not Leonardo’s last name.

John Cunnally, associate professor of art and design, has spent much of his life researching Italian Renaissance art and takes a group of students to Rome every summer. He says many of the facts presented in the book in relation to the works of Leonardo da Vinci are not only inaccurate, but “profoundly ignorant.”

“I find [the book] kind of annoying and offensive,” Cunnally says.

One of the claims the book makes is that in “The Last Supper,” the figure to the left of Jesus is not the disciple John, but actually Mary Magdalene. The book also concludes Magdalene was not a prostitute, but instead, has been portrayed as one by the Catholic Church.

Cunnally says there is no reason to believe the figure to the left of Jesus is Magdalene.

“No one in the 1490s would have thought it was a woman,” he says.

Wallace Tomasini has been a professor of art history at the University of Iowa since 1957. Tomasini says there is no evidence the person in the painting is Magdalene.

“The author Dan Brown’s conflation of a number of unrelated facts may make for some a wonderful story, but it has nothing to do with history,” Tomasini says. “It would be better to place this fiction in the same category with that of flying saucers … and those ancient superhuman heroes from outer space that have been suggested as [the] builders [of] the pyramids.”

Cunnally says the idea there are secret meanings in paintings is a myth art historians try to dispel.

FACT: In the fifth century, Pope Leo I wrote a letter to the public calling for the systematic destruction of apocryphal gospels. In letter 15 in “The Select Library of Nicene and Post-Nicene Fathers of the Christian Church,” Leo writes: “And the apocryphal scriptures, which, under the names of Apostles for a nursery-ground for many falsehoods, are not only to be proscribed, but also taken away altogether and burnt to ashes in the fire.” Today, 30 more gospels have been discovered in the addition to the four included in the Bible.

“The Da Vinci Code” also claims Magdalene was actually married to Jesus and was portrayed as a prostitute by the Catholic Church in an attempt to make Jesus more divine. The gospels that refer to Magdalene being married to Jesus were never included in the Bible.

Hector Avalos, associate professor of religious studies, said he can list 900 items that are correct in “The Da Vinci Code.”

“Would that make the whole book historical?” he asks. A general consensus would say no.

“The main premise of this book is not verifiable,” Avalos says.

Avalos says there is no way to determine whether Jesus was a bachelor. During his time, there were many different Jewish groups who had different traditions when it came to marriage.

Avalos says that as religion evolves, stories are developed and accepted, making fact-checking difficult — and this book illustrates that point.

“[This] just goes to show that even under the most modern circumstances, it is very hard to differentiate fact from fiction,” Avalos says.

Crystal Sullivan, campus minister for St. Thomas Aquinas Church, says the Bible has evolved since its start.

“It wasn’t like the people got up the next day after the resurrection and the Bible appeared on their bedside table,” Sullivan says.

FACT: There is no position of professor of religious symbology at Harvard University.

The book explains Emperor Constantine’s decision to unify the formerly pagan city of Rome under the veil of Christianity.

The pagan religion kept the tradition of balance and harmony in life, with men and women being equal. After Constantine’s decision, women took a lower level than men, according to the book.

David Hunter, professor of religious studies, says the switch from paganism to Christianity cannot be easily simplified.

“To say it was simply a business decision is an oversimplification,” he says.

Hunter says the decision made by Constantine to grant religious tolerance was personal and political.

He says Constantine was unsure of the substance of the Christian god but decided that if he supported Christianity, its god would continue to support him.

Hunter says the book is correct about the reuse of pagan dates. Historically, Dec. 25 was the Feast of the Sun, a pagan celebration for the winter solstice. He says the switch to a Christian celebration was probably chosen to oppose the pagan religion.

“At the time, it was sort of a triumph of Christianity,” he says.

Sarah Larsen Nelson, pastor at Lord of Life Lutheran Church, has been a pastor for 12 years and has seen the church evolve to include women again.

She says since her time in seminary school, the types of classes have changed to include women.

“Women seem to be a lot more interested in the history [of the church],” Nelson says.

Nelson says during the time of Constantine, women had a very powerful presence in the Church. Once the church came to the realization women were not nearly as powerful in society, the church began to take away their power in the church, she says.

“The history of the Catholic Church is written by the victors,” Nelson says, “and they were men.”