Da Vinci Code was an interesting read. And there are some things that have been found in correlation with some ancient texts and other things are simply amalgams of certain events and people. Such as Sognierre. I have found two Saugniers in French history. One was an actual museum curator but had little knowledge of the apocrypha(as far as I've read) and another Father Saugnier who was a Father(whatever you call it) of a church called Renne Les Chateaux who had found some ancient documents hidden in a pillar and for some reason decided to live a life of lechery, debauchery and evil. This life of his also included secret rituals held within the church. It is said that on his death bed he had a priest reside over him and hear his confession and after that priest had heard the confession refused to give saugnier restitution for his horrible crimes.

I must say this even things in that book which match up with the dead sea scrolls and the apocrypha should all be taken with a grain of salt. Those may be Holy men that wrote these things but holy men tend to stretch and bend the truth a little at a time till it is unrecognizable.