There isn't one item in the DaVinci Code that I had not heard or read before. So far, pretty much the same with the prequel Angels and Demons. But it is an interesting and fun read. There are some glaring technical errors, and the dialogue is rather hokey, but I set myself to enjoy the books as entertainment, and I was entertained.
Surprisingly a book that goes along with the DC book is Mists of Avalon, which touches Joseph of Armitrea (or whatever) living on Avalon and built the first christian church there of wattle and daub.
There is also a good explaination to a "virgin birth" in Mists. A virgin who gets with child at the rites of Beltane, Midsummer, Samhaim, or Midwinter festivals, or during other rites, are considered to have been impregnated by the god, as the woman is the goddess. Mary, a virgin girl of about 14 could well have taken part in a similar essene ritual.