Dan Brown would have struggled to come up with a tale more filled with pseudo-historical intrigue and claims of treachery than the one revealed in Court 61 of the High Court yesterday.
In the ornate setting of the Royal Courts of Justice in central London, the author of The Da Vinci Code, who made £45m in 2004 alone, finds himself being sued for allegedly ripping off the work of two biblical sleuths bent on rewriting Christian history, in order to provide the basis for his bestseller.
Such was the importance of the case being brought by the authors of The Holy Blood and the Holy Grail (HBHG) - which was published by Random House in 1982, and laid out the theory that Jesus was married to Mary Magdalene and left a traceable blood line - that the reclusive Mr Brown even made a rare public appearance to defend himself.
The case turns on the claim that Mr Brown infringed copyright by lifting the central premise of HBHG and used it as the plot for The Da Vinci Code - a shamelessly populist blend of historical conspiracy and murder mystery, also published by Random House, that was described by Salman Rushdie as "a book so bad it makes bad books look good" - which has sold 40 million copies since 2003. The proceedings against Mr Brown's British publisher, Random House, have generated nervousness as far away as Hollywood. The opening in May of the £53m film version of The Da Vinci Code, starring Tom Hanks, could be threatened by a victory for Mr Brown's opponents.
Richard Leigh, 62, and Michael Baigent, 57, two of the three authors of HBHG, claim Mr Brown owes them damages because their key theory - that the lineage of Christ married into the Merovingian line of French kings and is protected by a secret society based in France - forms the basis for The Da Vinci Code.
Lawyers for Random House argued that HBHG, which has sold about two million copies, was one of numerous sources consulted by Mr Brown and his wife, Blythe, an art historian, during research for The Da Vinci Code and claimed that their opponents were seeking to copyright history.
Jonathan Rayner James QC, for Mr Leigh and Mr Baigent, said his clients recognised their work was one of "historical conjecture". He added: "This case is not about stultifying creative endeavour. It is not about seeking a monopoly on ideas or historical data. [But] it is not as though Brown has simply lifted a discrete series of raw facts from HBHG. He has lifted the connections that join the points up."
He said that Mr Brown had ripped off the very specific thesis of HBHG to lend The Da Vinci Code "plausibility" and save himself the time and effort of independent research. If successful, the claimants could be awarded a share of the profits from the four million copies of The Da Vinci Code sold in Britain and a proportion of future sales.
The authors of HBHG claim that the name of the chief villain in The Da Vinci Code, Leigh Teabing, is a deliberate anagram of the surnames of Mr Leigh and Mr Baigent. But Mr Brown, from New Hampshire, said that he had developed the ideas in his novel long before reading HBHG.
In a witness statement, he said: "By the time we obtained a copy of Holy Blood, Holy Grail, I had already written the synopsis and the opening ... and had in place the themes." Lawyers for Mr Brown insisted that despite this, he had made clear his debt to the authors of HBHG by mentioning the book in The Da Vinci Code.
The acknowledgement is less than fulsome. When shown the cover of the book with the catchline "Acclaimed International Bestseller", Mr Brown's character exclaims: "An international bestseller? I've never heard of it." The case, which is expected to last two weeks, continues.
* The "central theme" of The Da Vinci Code - that the bloodline from a marriage between Jesus and Mary Magdalene survives today - is the key theory of The Holy Blood and the Holy Grail.
* The chief villain of Brown's book is Leigh Teabing. Mr Brown is accused of deliberately forming the name from an anagram of the surnames of the two authors of HBHG.
* Jacques Sauniere, the curator of the Louvre found murdered in the The Da Vinci Code, has the same surname as Berenger Sauniere, a monk mentioned extensively in HBHG.
* The Da Vinci Code mentions specific historical events - the Council of Nicea, which "voted" on the status of Jesus as a deity, and the connection between Godfroi de Bouillon and the bloodline of Jesus - which allegedly appear only in HBHG.Reuse content