It was only at the Council of Nicaea in AD 325, wrote Brown, that Jesus was said to be divine. Not quite. Jesus is called "God" seven times in the New Testament and is referred to as being divine on dozens of occasions. He was crucified not for being a prophet or an ethicist, or for that matter a champion of social justice, but for claiming to be the Son of God. 

There are numerous letters from pagan and thus objective writers from the first and second centuries, long before Nicaea, describing how Christians believe Jesus to be divine, including one written to the Emperor Marcus Aurelius, who died in AD 180. All the Council of Nicaea did was to affirm that Jesus was in fact the Son of God.

But Brown didn't stop there. The Dead Sea Scrolls are the earliest Christian writings in existence, opined our boy, and the Gnostic Gospels frequently mention Mary Magdalene and her marriage to Jesus. Actually the Dead Sea Scrolls are Jewish writings and have no direct connection with Christianity at all, and as for those much-discussed Gnostic Gospels, they at no time mention Jesus as being married to Mary.

But here's the point, and one that applies equally to the latest book. Dan Brown doesn't expect his readers actually to read the Gnostic Gospels or Dante, any more than he worries that they will know that there are no monks — albino or otherwise — in the largely lay Catholic organisation Opus Dei, or that the Emperor Constantine did not write any of the Gospels. He knows that if you say these things with apparent authority, and also imply that it's esoteric and dangerous knowledge, some of the more credulous out there will drink the unholy blood from the unholy grail. In other words, Brown condescends and relies on mass ignorance, and in the contemporary world there's a lot of it about.