American author Steve Berry has laid down a most remarkable challenge. The 58-year-old professor of law has a number of controversy-churning historical thrillers to his name, with The Amber Room (2003), The Romanov Prophecy (2004) and The Columbus Affair (2007) the most popular.

Now, however, Berry claims to have discovered proof of one of the greatest conspiracies of all time... and certainly one that could have enormous implications for the history of English monarchy.

In his book, The King's Deception, published in March, Berry claims that the Queen Elizabeth I whom history knows as Queen of England and Ireland, who ruled from 1558 to 1603, was not only an imposter, but male.

Berry alleges the real Elizabeth died of fever, possibly the plague, when she was 10 years old. Her governess, Lady Kat Ashley, and guardian, Thomas Parry, were apparently responsible for replacing Elizabeth with a boy from the Cotswold village of Bisley, in Gloucestershire. King Henry VIII, who had barely seen his daughter and was already suffering from severe health problems of his own, was apparently fooled when he visited her.

And so, Berry claims, a nine-year-old village boy ruled as Queen of England for over four decades. He points to one of Queen Elizabeth I's most famous speeches - to her troops at Tilbury - "I have the heart and stomach of a king, and of a king of England, too" as literal proof of his claim.

Bram, Stoker of Dracula Fame, Concurs

According to the Mail Online, Berry's claims have some interesting supporting narratives. It appears that Bram Stoker, the author of Dracula, believed in stories that a clergyman in Bisley had discovered the skeleton of Elizabeth I. Stoker included details of this possible deception in his fourth non-fiction work Famous Impostors; click here to read the e-book.

St Edward's Crown

After writing on Elizabeth's early years (up to the age of 10), to establish her character, intelligence and traits as with "an amount of knowledge in all branches of learning sufficient to equip the illustrious men of a century", Stoker moves to 1544... when she would have been 11 years old.

Stoker's research led him to believe that Elizabeth underwent a dramatic change over the preceding 12 months, becoming "secretive" and "took few into her confidence, unless it was of vital necessity".

Perhaps more tellingly, Stoker writes: "In the year which had elapsed since her last recorded letter Elizabeth's literary style had entirely changed. The meagre grudging style has become elegant and even florid with the ornate grace and imagery afforded by the study of the Latin and French tongues."

Roger Ascham's Letter

Both Stoker and Berry reference a letter written by one of Elizabeth's tutors - a Roger Ascham - who wrote to a Rector at the Protestant University in Strasbourg: "The constitution of her mind is exempt from female weakness, and she is endued with a masculine power of application."

And both Stoker and Berry point to several other comments and observations, made by people familiar with the royal court and the Queen herself, with Lord Somerset reportedly told: "I do verily believe that there hath been some secret promise between my Lady, Mistress Ashley, and the Cofferer [Thomas Parry, the principal officer of the court] never to confess to death."

So... is it true? Was Queen Elizabeth I an imposter? Is the real daughter of Henry VIII buried in an unmarked grave somewhere in Gloucestershire?