On a day heavy with emotion, the future king made a poignant pilgrimage to the picturesque harbour village where his great-uncle was murdered by the IRA.
Prince Charles was warmly greeted as he arrived in Mullaghmore on the west coast of Co Sligo.
The visit came almost 36 years after the bombing which killed the man he affectionately described as the grandfather he never had.
The prince met members of the community who helped in the rescue operation after Lord Louis Mountbatten's boat was blown up.
He also met relatives of some of the three others who died in the bombing.
It was the most poignant leg of a four-day visit to Ireland by the prince and the Duchess of Cornwall, which continues today when they travel north.
Last night the brief stop-off was hailed as a huge step forward in Anglo-Irish relations.
A place of beauty, Mullaghmore has long been burdened by its past and the terrible events of August 1979.
Lord Mountbatten died when the IRA blew up his fishing boat the Shadow V as it sailed in the waters off Mullaghmore.
Nicholas Knatchbull, the earl's 14-year-old grandson, and his friend Paul Maxwell, a schoolboy from Enniskillen, who had worked on preparing the royal boat for fishing, were also killed.
The Dowager Lady Brabourne (83), the mother-in-law of Lord Mountbatten's daughter, died a day later.
Yesterday's visit was seen as a highly symbolic yet hugely personal journey for the prince, reaching out across decades of hurt.
Earlier, he had reflected on his sense of loss.
"At the time I could not imagine how we would come to terms with the anguish of such a deep loss since, for me, Lord Mountbatten represented the grandfather I never had," he told an audience in Sligo.
The remarks came ahead of a peace and reconciliation prayer service in nearby Drumcliffe attended by Charles and Camilla.
From St Columba's church, where the royal couple paused at the grave of literary great WB Yeats, they travelled northward to Mullaghmore.
The visit took place amid a backdrop of tight security, following the arrest of six people last week over an alleged dissident IRA plot. A helicopter kept watch overhead while scores of gardai patrolled the normally sleepy seaside community.
After a private visit to Lord Mountbatten's summer retreat of Classiebawn Castle they arrived in the village around 5pm.
Among those who greeted the prince was Peter McHugh, one of those most closely associated with efforts to rescue the Mountbatten party.
The couple also met Kevin Henry, a retired garda who was on security detail for Lord Mountbatten when the IRA struck.
He saw the aftermath of the bomb from the headland above the village. Others included Elizabeth and Richard Woodmartin who pulled Timothy Knatchbull from the water after his brother Nicholas suffered fatal injuries.
Mr Knatchbull accompanied Charles and Camilla on their short tour of Mullaghmore with his wife Isabella.
Members of Paul Maxwell's family, including his father John and mother Mary, met Prince Charles privately in the Pier Head Hotel.
At the slipway to the harbour, from where Lord Mountbatten set out to sea that morning, Mr McHugh pointed out the area around the bay to the prince.
Afterwards Mr McHugh told the Belfast Telegraph that he hoped it could heal decades-old wounds. "It was at times quite an emotional occasion because it just brought back the memories of what happened on the day. Today is just another step on the healing process," he said.
Mr McHugh said Prince Charles had expressed contentment at visiting Mullaghmore.
"He mentioned several times the fact that he thought he would never be in a position to come here, so obviously it's been something on his mind for quite some time," he added.
"I think he's hugely relieved that he has come here and I think it will be of huge benefit to him."
Tony Heenan, a consultant at Sligo General Hospital who helped to revive the injured from Shadow V, also met the couple.
"It doesn't matter where you come from or who you are, it's still a huge loss, and it sometimes can't be measured," he said.
Mr Heenan said he hoped yesterday's events brought Prince Charles comfort. "I think that's what everyone wants - the healing. It takes a little time and it can be difficult, but it does happen and it will happen, and he has all the signs of a man who has been healed."