When he passes through Sligo on Wednesday, it won't be "bare Ben Bulben's head" that will catch the imagination of the Prince of Wales, but the long, icy shadow cast by Classiebawn Castle and the events of an August weekend all of 36 years ago which changed so many lives forever.
"My heart literally sank," said Prince Charles some years later as he recalled the brutal IRA bombing that ended the life of his grand uncle and mentor, Lord Louis Mountbatten.
The events of that August day also cast a long shadow over the life and death of Ireland's first 'beef baron' Hugh James Tunney and his partner Caroline Devine, who leased the castle from Mountbatten at the time and later bought it from the family.
Hugh Tunney's own peaceful passing so many years later was largely marked because of his association with Classiebawn and the tragic events with which it has become so intertwined.
It was a classic case of role reversal: the owner of Classiebawn Castle, Lord Mountbatten of Burma, godson of Queen Victoria and the Emperor of Russia, Viceroy of India, a member of the royal's inner circle; and Hugh Tunney, the son of a cattle-dealer from Co Tyrone who, while working as a butcher in nearby Bundoran, had looked at Classiebawn, and resolved one day to own this castle, built by another quintessential pillar of the British establishment, Lord Palmerston.
Yet according to Timothy Knatchbull, one of the tragic family who left Mullaghmore pier that morning to go fishing for mackerel on board their launch, Shadow V, his grandfather Lord Mountbatten and Hugh Tunney, "this odd but engaging man", got on "surprisingly well" after Mountbatten invited Tunney to dinner at his home in London's Belgravia to discuss the future of the castle.
The fact was that Mountbatten, for all his honours and his place in the inner circle of the British royal family, couldn't afford the upkeep of the enormous castle - Tunney, a self-made devoutly-Catholic multi-millionaire cattle dealer, could. But what bonded them most was a grand passion to keep Classiebawn Castle from becoming just another romantic Irish ruin.
Although he died in 2011, Hugh Tunney's will, which valued his estate in Sligo property in Monaghan, Dublin and Laois - including 'my' island in Lough Erne - at €8,204,591, only went to probate in Dublin two weeks ago. It too passed with hardly a mention because Tunney, in life and in death, tied his affairs up in a complex web of companies and Isle of Man Trusts which went to the benefit of his children, Hugh Tunney Jnr, James Tunney, Mauretta Flynn and Nuala McGonagle.
In this will, dated April 27 2009, his executors are named as Brian Bailey of the Dublin solicitors firm Lavelle Coleman and Caroline Devine, whose address is given as Loughrey, Co Galway, although in company documents she continues to be domiciled in Classiebawn Castle.
According to the eminent chronicler of Irish castles and houses, Mark Bence-Jones, Classiebawn is "a Victorian baronial castle spectacularly situated on a bare headland jutting out into the Atlantic" built by the British statesman Lord Palmerston towards the end of his life. Indeed, he is said to have come to Ireland to watch its construction.
It was left to his wife's grandson, the Rt Hon Evelyn Ashley, MP, and passed from him to his granddaughter, Countess Edwina Mountbatten. On her death, it passed to her husband, Earl Mountbatten, who took time out from the Second World War to pay his first visit there in 1941. Along with members of his extended family, he habitually spent the month of August at Classiebawn, living quietly and unobtrusively and blending in with the local community who were fiercely protective of their royal visitor.
But by 1975 the British aristocrat could no longer afford the upkeep of the castle and in desperation wrote to the then-Taoiseach, Liam Cosgrave, offering it to the Government. The offer was "graciously declined" because of the costs associated with the renovations and upkeep, which were now much needed. A local auctioneer then told Lord Mountbatten that a local man, Hugh Tunney, who had "made good" was interested in acquiring a lease on the castle.
The eldest of nine children from Trillick, Co Tyrone, Tunney emigrated to London in 1953 and worked in the cattle business for a couple of Irish dealers, the Mollaghan brothers. When asked where he went to school, his reply was "the University of Ardagh" - a reference to the village where the Mollaghans came from in Co Longford.
He started his own business in Belfast and by the mid-1970s he was a multi-millionaire with meat plants in Clones, Co Monaghan, and Belfast. He also owned the Gresham Hotel in Dublin for a brief period, and after selling out he kept a suite in the hotel for many years. He also owned the Talbot Hotel in Wexford and was involved in prolonged and bitter litigation over another of his hotels, Sach's Hotel on Morehampton Road in Dublin.
A man of few words, if he had anything to say he usually said it through his lawyers.
After meeting Mountbatten in London, Hugh Tunney signed a 21-year lease on Classiebawn in January, 1976, agreeing to pay rent of £3,000 a year and carry out the renovations that were needed. There was also a clause in the lease allowing the Mountbatten family to occupy the castle for the month of August each year. "My grandfather was hugely relieved to have found a way of securing Classiebawn's future. He was happier there 'than anywhere else on earth' and I felt the same," writes his grandson Timothy Knatchbull in his memoir of life and death in Classiebawn, 'From a Clear Blue Sky.'
On August 27, 1979 an IRA bomb shattered their Irish idyll. Hugh Tunney was also staying in the castle, as one of the party remembered interrupting hime as he said his morning Rosary. Although he didn't go on the family fishing expedition, the events of that day would haunt him and the castle for the rest of his life.
When the IRA bomb went off, Lord Mountbatten, his grandson Nicholas Knatchbull (14), and Paul Maxwell (15), who was crewing the boat, were all killed instantly.
The Dowager Lady Bradbourne (83) died the following day and Timothy Knatchbull and his parents, although critically injured, survived. Their dog Twiga was also killed in the blast and is buried in the grounds of the castle.
The castle and estate was sold to Hugh Tunney in 1991 and he moved from his home in Clones, Co Monaghan, to live full-time in the castle with Caroline Devine.
But what had once been a dream became something of a nightmare for the tough, uncompromising meat baron. Ironically, the aristocratic Mountbatten had been tolerant of local indiscretions, like people grazing cattle on his land, but Tunney was having none of it and soon fell out with staff and local people who found him domineering and intolerant.
Describing his return to Sligo in 2003 for the 24th anniversary of the explosion, Timothy Knatchbull paints a picture of a lonely figure living in the dark past.
"Over the years Hugh had become increasingly isolated from village life. Although he went to church daily, he told me that in the previous 20 years he had only been to a local pub twice," Timothy Knatchbull recalls in his memoir.
"He chose to minimise the number of people who were allowed up to the castle. Caroline seemed to do most, if not all, of the housework, cooking and cleaning. Most of the castle was shuttered, dusty, damp and cold. Many of the rooms were crammed with objects bought by Hugh and slotted in and around the furniture, pictures and possessions we had left behind. The effect was ghostly and gave me the impression of visiting a monument, even a mausoleum."
For Prince Charles it won't be the castle itself - after all, he's a man of many castles - but the significant part it played in the life of a man who represented the British establishment at the highest levels, yet valued his casual Irish inheritance at Classiebawn and Mullaghmore more than anything else in life.