The extraordinary find came to light after seven years of investigations by a Coventry-based historical researcher, Dr Graham Phillips, who tracked the potential "relic" down to a house in Rugby, Warwickshire, where its owner kept it in a box in the loft.
Dr Phillips has unearthed a substantial body of evidence linking the find - a small green onyx cup of possible Roman date - to the Grail legend.
In the medieval Arthurian romances, the Holy Grail was the cup used by the man who buried Jesus - Joseph of Arimathea - to collect Christ's blood. However, the origin of the medieval legend appears to have been a real historical grail "found' in the 4th century AD by the newly-Christianised Roman imperial authorities who turned it into a sacred relic.
According to the 5th century Greek historian, Olympiodorus, this original Holy Grail had been used by Mary Magdalene to collect Christ's blood and was found by the Christian Roman empress, Helena, inside Christ's Holy Sepulchre.
Olympiodorus also recorded that the sacred vessel was first taken to Rome and then in the early 5th century spirited away to Britain to protect it from the barbarians. It is this historical grail - or a later substitute - which appears to have now come to light. Dr Phillips is publishing the evidence in a book,due out next week.
Before Dr Phillips's research work, Helena's historical grail was the only one associated with Mary Magdalene. All other references link the grail, if to anybody, to Joseph of Arimathea. What Dr Phillips has succeeded in doing is unearthing three other Magdalene-related grail references - all of which are in Shropshire, and all of which are associated with a Shropshire family who were descended from the kings of Powys. The Magdalene connection crops up in relation to the grail and the family in c1200 (a manuscript), c1600 (a poem) and 1850 (a secret code). Because the only grail associated with Mary Magdalene was - until Dr Phillips's research - the one "found" by Helena, and because the only historical source says it came to Britain, the Shropshire grail tradition (also associated with Magdalene) could be linked to that of Helena's grail.
The historical grail seems to have left Rome for Britain around 408AD when the barbarians were threatening the city. However, the imperial authorities, desperate to defend Rome, withdrew their legions from Britain. Dr Phillips believes the grail was then moved to Shropshire. The main city in that area was the capital of the local state, later the kingdom of Powys. The king's family then remained involved in the grail saga until this century.
Dr Phillips tracked the story on through the centuries until he discovered the present descendant, Victoria Palmer, 24, a graphic designer from Rugby, who still had the cup - but had no idea of its potential significance. The cup - which was originally found by her great-grandfather in a cave at Hawkstone Park, Shropshire - is now in a bank vault.
9 The Search for the Grail, by Graham Phillips; is published by Century; pounds 15.99.Reuse content