Part of The DaVinci Code's popularity is surely its fascinating plot.  To summarize: Christ was deified by Constantine the Great in A.D. 325 at the Council of Nicaea.  The "Priory of Sion" (supposedly founded in 1099) knows the "truth": Jesus was a man, married to Mary of Magdalene.  The couple had a daughter they named Sarah, who was raised in France; her bloodline can be traced to this day.  Her tomb and story are the "Holy Grail," the "cup" containing the "blood" of Christ.

Leonardo daVinci was Grand Master of the Priory of Sion from 1510-19.  In this capacity, he used artistic means to tell the "truth."  His The Last Supper pictures Mary Magdalene at Jesus' right hand.  His Mona Lisa was named for Amon (the Egyptian male god) and Isis (their female god), intended to show the union of man and woman.

However, the Roman Catholic Church's most militant sect, Opus Dei, has attacked the Priory of Sion before it can release its "truth" to the world.  As a result, the current Grand Master of the Priory, Jacques Sauniere (curator of the Louvre), must pass the key to the location of the Holy Grail to his granddaughter, Sophia Nevea.  Robert Langdon, a Harvard professor of religious symbology, helps her find the key and the path to the Grail, with the assistance of renowned English historian Leigh Teabing.

It's a fascinating plot.  Each character is of course fictional.  And so many dismiss concerns over the book's claims, citing the fact that the work is a novel.  However, Mr. Brown claims that his plot is built on historical truth.  The first page of his book is titled "Fact."  It ends with this claim: "All descriptions of artwork, architecture, documents, and secret rituals in this novel are accurate" (p. 1).  By "documents" he means the descriptions of the Bible and its origins, the Gnostic gospels, and other documents we'll discuss momentarily.

In interviews, the author has made clear that he believes what his novel claims: that Jesus was a man deified by Constantine; the Church covered up the real records; and orthodox Christian theology is founded on this deception.  His book makes the case with authority, placing these assertions in the mouths of the Harvard professor and his expert friend.  When Tom Clancy describes Jack Ryan on a submarine, we know Ryan to be a fictional character but we assume his description of the submarine to be accurate.  It is the same with Mr. Brown's depiction of the historical "facts" behind the Christian gospel.  It is impossible to tell in the novel where historical fact and fiction separate.

Clearly, many readers have not made the distinction.  Celebrities have been quoted with gratitude for Mr. Brown's exposing of the truth behind the Christian movement.  I have spoken with a large number of people in recent months who assume the novel's portrait of Christian origins to be accurate.  Even many who claim a strong personal commitment to Christ are confused.  They don't believe what the novel claims, but don't know how to respond to its falsehoods or explain the truth to others.