Over a hundred years ago, in a little village in France, the local priest made a revolutionary discovery. "He was renovating the church and found a pillar that was hollow. And in this hollowed-out pillar, there were some parchments", explains Henry Lincoln, author of 'Holy Blood, Holy Grail'. He took the documents to the ecclesiastical authorities in Paris and returned a wealthy man. "There are theories that he was blackmailing the Vatican because he discovered something that would undermine the Church."

Some people believe priest Berenger Sauniere discovered documents proving that that Merovingian Dynasty were direct descendents of Christ. "The Priory of Sion claimed to be the people giving Sauniere his money," explains Prince. "They said Sauniere discovered documents that revealed the truth about the survival of the Merovingian Dynasty."

One of the members of the Priory of Sion was Leonardo da Vinci. "Leonardo was a heretic", states Dan Burstein, author of 'Secrets of the Code.' "He was unable to express his attitude towards the Catholic Church openly so he did it through the codings in some of his paintings."

'The Last Supper' is undoubtedly one of the most famous of Da Vinci's work. "Everybody recognises it, art historians have been over it with a fine tooth comb, but no one seems to have noticed interesting facts," points out Lynn Picknett, the first person to decode the paintings. Strikingly, Da Vinci has painted a woman sitting next to Jesus, who seems to be joined to him at the hip. "Jesus is wearing a red robe and blue cloak and this character is wearing the opposite ... It suggests Leonardo is trying to say that Mary Magdalene was at the last supper, sitting next to Jesus as his other half."

As a member of the Davidic line, Jesus was required to marry and sire two sons by the age of 40. Authors like Margaret Starbird argue that the wedding of Cana was actually Jesus' wedding to Mary Magdalene. And legend states it was Mary Magdalene who bought the Holy Grail, the Sangraal, to France after Jesus' death. "If you divide the word Sangraal after the G it means blood royal", states Starbird. "And you don't carry the blood royal in a jar. It flows in the blood of a child."

"Mary Magdalene is the most important woman in world history," claims Lynn Picknett. "Not for what she did but because Church fathers were so afraid of her image." In the bible, she barely exists at all. But in the unauthorised Gnostic gospels, she takes centre stage. "She's feisty, she's assertive. She annoyed the male disciples immensely because she had such power over Jesus," states Lynn Picknett.

By negating Mary Magdalene's role, the Church's founders were able to justify male supremacy. Even now, it argues that women cannot be ordained because Jesus had no female disciples. As Picknett claims "The whole of history, the way that the Church has treated its women, is actually because of their terror of Mary Magdalene."

True or not, the theories in the Da Vinci Code are entertaining and influencing millions of people. In this high quality production, the authors and researchers whose work shaped Dan Brown's novel explain their ideas.