Dan Brown's saving error

In the latest twist in the legal action faced by Dan Brown, accused of plagiarising another book to write his bestseller The Da Vinci Code, it seems that historical inaccuracy might come to his rescue. As Alan Hamilton writes in The Times:

According to [Brown] the Priory of Sion, alleged keeper of the secret of Christ's wife and children, was founded in Jerusalem during the Second Crusade in the reign of Baldwin II. But according to the authors of The Holy Blood and The Holy Grail, who are suing Brown for stealing their plot, the Priory was founded in 1099 during the First Crusade, and Baldwin did not ascend the throne of the ancient city until 1118.

The case is a reminder of how difficult it is to make a legal challenge to authorship. Unless something is copied word for word then it seems almost impossible to judge that plagiarism has occurred. A single chink in the prosecution case, (see above) can be enough for the defence to win.