Dan Brown, author of the wildly successful The Da Vinci Code, is being sued by two of the authors of The Holy Blood and the Holy Grail (HBHG) for plagiarism.

The problem they have is that countless books written in the wake of HBHG have mined that book for facts and ideas. Moreover, thousands of copies of HBHG were sold off the back of Da Vinci, which has generated a whole publishing industry in its trail.

The interesting question is, have those ideas gained common acceptance, especially among leading authorities in the field?

Quite a number of Biblical scholars have written books broadly agreeing with many of the points brought out in HBHG. The Templar fortune, for example, and the “treasure” of the Cathars — thought to be the Coptic Gospel of Thomas, have been much discussed. The “Priory of Sion” may or may not be the genuine article, but the concept of Rex Deus, a group descended from the priests of the Temple in Jerusalem, seems to have a strong foundation in fact.

The Gnostic Gospel of Mary shows Mary Magdalen to have been much more than a common harlot. Respectable scholars now believe she was Mary of Bethany, and some say the wedding there was Jesus’s own to Mary. So, children would not have been out of the question.

There is alleged to be a document in the Vatican library dated 37AD which tracks Joseph of Arimathea’s journeys to Britain, and persistent rumours and historical echoes have come down to us in folk tales and various accounts.

That Mary might have escaped to the South of France and inadvertently founded the Merovingian dynasty is credible given the many references to Mary and Mary Magdalen in churches in the region.

Any analysis of the conventional Gospels show them to be contradictory and historically inaccurate. They were most probably rehashed from older Egyptian sources, involving Horus, a god born to a virgin mother, Isis, then murdered and resurrected miraculously. These already-ancient ideas would have been grafted on to memories of a local holy man in order to bolster his claims in the very competitive religious marketplace of the time.

My book, COSMOSITY, shows that all these powerful echoes relate to a mystical state, which I call Nirvanic experience (to avoid religious distortion), and which demonstrates the immortality of consciousness.

There’s probably some deep underlying truth in both HBHG and The Da Vinci Code. But, like a dream, the details appear garbled when reviewed after the event.