A phone call from a friend over 20 years ago set a Ruthin man on a mission to solve a puzzle which has long intrigued historians and academics – did the Britain’s greatest ever playwright spend time in North Wales?

Author and former university lecturer John Idris Jones is more convinced than ever that William Shakespeare stayed in Denbigh and Hawarden, and he has presented his argument in a newly published book titled Shakespeare’s Missing Years.

His interest in the subject was triggered by antiquarian bookseller Tom Lloyd-Roberts from Caerwys, an expert on Welsh history, especially the Tudor period.

Mr Lloyd-Roberts highlighted the fact that although it was known that Shakespeare was born in 1564 there was no record of his schooldays. Similarly, after his marriage to Anne Hathaway and the birth of their three children, practically nothing else is known of his early biography up to 1592.

Tom Lloyd-Roberts’s research led him to believe that Shakespeare not only stayed with his friend Sir John Salusbury at Lleweni, Denbigh, during the winter of 1592-94 but wrote some verses which are now in the possession of Christ Church, Oxford.

His theory was supported by Robin Reeves, then editor of The New Welsh Review, and John, who has carried out much of his own research since then, says the book is dedicated to them.

“I owe them a debt of gratitude; they opened a subject which has invigorated my life,” he said.

“Hundreds, if not thousands of books have been published, including biography and literary theory and yet a large part of his biography is incomplete,” he said. “Biographers have found this to be an embarrassing problem.”

John Salusbury, the son of Catrin of Berain, great-granddaughter of Henry VII, is known to have been a friend of the bard and Shakespeare contributed to Love’s Martyr a volume published in praise of him.

He and his wife Ursula are believed to be the subject of the poem The Phoenix and the Turtle which is said to contain several oblique allusions to Lleweni and the nearby Clwydian hills.

“Some items of language and some topographical imagery used by Shakespeare can be seen as supporting the proposition that he spent time in Lancashire and in north-east Wales,” said John.

Particularly intriguing is a poem among the papers at Christ Church, Oxford, which John has dubbed the “Denbigh Poem”. It describes John Salusbury and his wife in glowing terms and says that the writer visited their home in Denbigh.

John said: “I’m 100% confident Shakespeare spent time in Denbigh because of the so-called Denbigh poem.

“It’s clear the writer stayed with the Salusburys and in my view it’s penned and created by Shakespeare when he happened to be in the area escaping the plague in 1593, that’s the essential story.

“The house they were in still partly exists at Lleweni.”

The handwriting has never been verified but the respected linguist Professor David Crystal says it contains words which are typically used by Shakespeare at the time.

John Salusbury’s wife Ursula was brought up at Hawarden Castle which, John believes, could be the setting for Shakespeare’s poem A Lover’s Complaint as there are numerous potential references to local features and characters.

Though his research points to the bard having stayed in the area John, who taught English literature at the Northern Illinois University and Cardiff University, and is a Fellow of the Welsh Academy, concedes that firm evidence of his presence is still lacking, and it could lie in old family papers or book.

“I hope my book might raise awareness in this area so that when new material does emerge, its significance can be better identified and understood,” he said.

His hypotheses are backed by Professor David George of Urbana University, Ohio, who wrote: “His book should point to a new direction for the young Shakespeare’s biography.”