For most of the last 2,000 years, the Catholic Church called Mary Magdalene a prostitute who gave up her sinful life to follow Jesus.
But some people believe that Mary Magdalene was maligned through the centuries, and that she actually played a much more significant role in Jesus' life: as his wife, the mother of his child, and the most important of his disciples.
The truth, they believe, was deliberately suppressed by church leaders. There is a theory that the truth about Mary was kept alive by a secret society known as the Priory of Sion, whose members included some of the greatest artists and thinkers of Western civilization, including Leonardo Da Vinci.
Author Dan Brown believes the renaissance master encoded the truth in some of his most famous paintings. His best-selling book, The Da Vinci Code, has a lot of people talking these days. The book is a novel, but author Dan Brown says much if it is drawn from historical evidence.
To investigate some of the claims in the book, ABCNEWS' Elizabeth Vargas traveled from one edge of the Mediterranean to the other. She found that not all the claims in the book are credible, but that some of them appear to have elements of truth.
The depiction of Mary Magdalene as a prostitute has its origins in interpretations of Luke's gospel, where it says she was cured of seven demons.
She's also introduced Luke right after a story about a prostitute whom Jesus forgives for her sins. In the year 591, Pope Gregory the Great overlapped the two identities.
The Vatican eventually corrected that impression, but not until 1969, 1,378 years later.
Brown believes the church allowed the confusion to obscure the truth about Mary's relationship with Jesus.
Scholars said the confusion has eclipsed important information the Bible does provide about Mary Magdalene.
"She's perhaps the most frequently mentioned woman who is among the followers of Jesus in the Gospels of the New Testament," said Biblical scholar Elaine Pagels.
The Rev. Richard McBrien of Notre Dame University said he thinks Mary Magdalene would have been recognized as one of Jesus' main apostles — and possibly the key apostle — had she been a man.
Margaret Starbird, who wrote several books that Dan Brown relied upon in writing The Da Vinci Code, said the Bible suggests she might have been Jesus' wife.
The Gospel according to John tells the story of a woman named Mary who anoints Jesus' feet with oil and wipes it away with her hair which is a marriage ritual, she said. And even though the woman is identified as Mary of Bethany, not Mary Magdalene, Starbird believes they are the same person.
In his novel, Brown says there is an apparent omission in Leonardo Da Vinci's famous painting "The Last Supper": the Holy Grail, or the chalice from which the disciples allegedly drank their wine, is missing, he said.
But he says the Holy Grail actually is there, on the right hand of Jesus. He says the grail is the figure to the right of Jesus — commonly thought to be John, but actually Mary Magdalene.
Some versions of the legend of the Holy Grail say it was taken out of Jerusalem and hidden away in Europe for centuries. Another legend holds that Mary Magdalene arrived on the coast of Provence in southern France with a boatload of Jesus' followers sometime after the crucifixion.