"The DaVinci Code"
and "Holy Blood, Holy Grail"
have been "accepted"
as reasonable
histories by many folk.
If they accept those . . .
You have to look at the hostory of the church and not just respond to novels. The churh has bben rife with corruption and politics at many times. After the burning of the library at Alexandria, the church became the biggest repository of books in the world. That's a lot of power and history in the hands of sometime corrupt popes and some who would act out of politcial motivation and their perceived need to protect the church from heresy.