Don't Lend Too Much Credence To It
The DaVinci Code is an interesting read. However, one should keep in mind that it is a work of fiction based on research mixed with speculation and imagination.
Excerpt from reviews on Amazon.com:
"...The Holy Grail, the Knights Templar, and the Priory Of Sion are extremely fascinating topics. However, as clever as the author (of the DaVinci Code) would seem, he simply borrowed the research of others (read Holy Blood, Holy Grail) and wrapped it up in a paint by numbers thriller."