Cracking the code

THE last time Oliver and Sheila Lawn encountered a code like this, Britain was facing the darkest hours of the Second World War. The couple were part of a team working on cracking German military codes at Bletchley Park, Buckinghamshire, and were among those credited with shortening the war by as much as two years because of their work.

Now, 60 years later, they are being called upon to crack another enigma. Mr Lawn smoothes his hand over the ten capital letters which are etched into the marble tablet known as Shepherd's Monument, in the grounds of the Shugborough Estate in Staffordshire. Today, instead of trying to crack the codes of a foreign enemy, the Lawns are hoping to reveal whether the letters - D.O.U.O.S.V.A.V.V.M. - can pinpoint the location of one of the most enduring symbols of Christian legend - The Holy Grail.

The very mention of its name brings to mind images of King Arthur and his knights; dramatic quests undertaken to secure the secrets of life and the power of God. According to legend, the Grail possesses the ability to heal the mortally wounded, give eternal youth and provide constant food.

Historians and mythographers across the world have cast a thousand theories on its existence and the mystery behind it has stirred the souls of poets, artists and writers for hundreds of years.

The story of the Grail varies greatly but versions share similar characteristics. It is said generally to have been the sacred vessel that Jesus filled with wine at the Last Supper and passed to his disciples, instructing them to drink his blood. In early historical versions it has also been seen as the dish from which Jesus ate the Paschal lamb with his disciples. The term 'grail' itself is believed to originate from the Latin 'gradale' meaning a dish used during a meal.

In some writings, Joseph of Arimathea collected the blood of Christ in the vessel after he died on the cross, before fleeing to Glastonbury in England with the cup, and establishing a castle, where his family and descendants guarded the Grail.

Early romantic accounts talk of a knight called Perceval or Parzival, going in quest of the Grail, stories which later became mixed with Arthurian legend, with Perceval becoming a Knight of the Round Table.

From the Grail's first appearance in an unfinished poem entitled, Conte del Graal, written by Chretien de Troyes in 1180, some authors have emphasised the Christian element and others the mystical, with a smattering of Welsh, Celtic and Irish lore blended in.

Intertwined with the legend of the Grail has been the story of the knights who have guarded it - the Knights Templar. The Templars or Poor Knights of Christ were a monastic order from Jerusalem founded in 1118 in the aftermath of the First Crusade to protect pilgrims in the Holy Land. The order has been surrounded by mysteries since ancient times, including its association with a secret society called the Priory of Sion which was concerned with the preservation of the Grail and whose alleged Grand Masters included Leonardo da Vinci and Isaac Newton.

Dan Brown's best-selling historical novel, The Da Vinci Code, refers to cryptic messages supposedly incorporated by da Vinci into his artwork. In the novel, the Priory of Sion is dedicated to preserving the "truths" that Jesus and Mary Magdalene were married and that the Holy Grail of legend is really Mary herself - a sacred feminine vessel who carried Jesus's children. Brown says that in da Vinci's painting of the Last Supper, John the Evangelist is actually Mary Magdalene.

He points to a lack of a central chalice as proof that the Grail is not a material vessel.

Brown's novel has been criticised by the Church and by scholars for its inaccuracies. Although he says that there is evidence of the Priory of Sion's existence in the French national library, it is widely purported that the "evidence" was planted there by the fraudster Pierre Plantard, who declared it fake in 1967.

But the stories surrounding the secret sect continue at the Grecian monument surrounded by rhodendrum bushes in the Shugborough Estate. In May, managers of the estate invited veteran codebreakers, including Oliver and Sheila Lawn, and some of their modern counterparts from GCHQ, the government's communication headquarters in Cheltenham, to try and decipher the mystery behind the ten letters, which have baffled visitors since 1748.

Theories abound, including ideas connected to numerology, UFOs, secret messages to lost lovers and even Nostradamus. But after several months of work, the claim of an anonymous US researcher is being highlighted.

The researcher, who has worked in defence, has applied standard codebreaking methods by a process of substituting one letter for another, while bearing in mind the historical context. He believes the message is likely to stand for "Jesus (As Deity) Defy" - a message of Christian defiance from the Priory of Sion, which believed Jesus was not a divine figure. The Order had to keep its views secret as the Church of England considered them heretical.

The historical context he has taken into account stems from Admiral George Anson, who commissioned the monument and who is an ancestor of the Earl of Lichfield, whose ancestral home is Shugborough. The Anson family has long had connections to the Priory of Sion.

There is another theory that Admiral Anson captured a ship which contained an old stone tablet handed down from the Old Testament prophet Jacob, and that the tablet was a talisman of the Priory. The theory goes that Anson buried the tablet on an island off the coast of what is now Nova Scotia, Canada.

When he returned to Shugborough, he built the monument, which incorporates a carved mirror image of Arcadian Shepherds, a painting by Nicolas Poussin, the 17th-century French artist who also has links with the Priory of Sion and the Knights Templar.

The research argues that the letters in their Latin form could also be masking the message: "In Acadia go". Acadia was the old French name for Nova Scotia and New Brunswick in modern Canada and thus could be a veiled instruction for his ancestors to go to Nova Scotia.

The mystery will continue to provoke countless theories. Mrs Lawn believes it could simply be a tribute from a lovelorn widower to his wife and her sister. Mr Lawn, who worked on cracking the Enigma Code at Bletchley during the Second World War with Alan Turing, says there can never be a conclusive theory.

"For any code, you need a minimum amount of encoded material, very much larger than ten letters," he says.

"No code of ten letters is possible to break definitively."