Princess Diana married Prince Charles in a lavish royal wedding ceremony in 1981, but their union ended in a huge disaster. Years after their divorce, a royal expert revealed that one event could have stopped their unhappy union.

It is not a secret that Prince Charles and Princess Diana had a turbulent marriage. However, this could have been prevented if not for the shocking assassination of Prince Charles’ uncle, Lord Louis Mountbatten.

A pivotal figure in the life of Prince Charles, Lord Louis died in an IRA bombing two years before the wedding of Prince Charles and Princess Diana. His shocking assassination shook the royal household in 1979 and significantly impacted the Prince of Wales, who shared a close relationship with him.

In his 2005 book “The Firm,” royal biographer Penny Junor revealed that Lord Louis could have advised Prince Charles not to marry Diana if he had not died two years before their wedding. According to him, Prince Charles valued his uncle’s words so much that he certainly would have taken heed had Lord Louis told him not to proceed with the wedding.

“Michael Colborne (Charles’ former secretary) is convinced that if Lord Mountbatten, murdered by the IRA in 1979, had still been alive a year later, Charles and Diana would never have married,” wrote Junor.

“He is probably right. None of them had the influence over him that Mountbatten had. Mountbatten was like a father to the prince and he would have seen that Diana was the wrong person for him to be bound to for 50 years or more,” she added.

According to Junor, many of Prince Charles’ friends had advised him prior to the royal wedding not to marry Princess Diana, but the Prince of Wales refused to listen to them because their opinions did not matter much to him as much as Lord Louis’ opinions did. “But Mountbatten was dead, and Charles was still consumed by grief, lost without the older man to guide him, and alone,” Junor wrote.

However, another royal expert said that even if Lord Louis were still alive when Prince Charles proposed to Diana, the Prince of Wales would still probably marry Diana because the Queen Mother was very keen on their match.

Prince Charles and Princess Diana Picture of Lady Diana, Princess of Wales, with Prince Charles of Wales at their wedding at St. Paul Cathedral in London in this file photo dated 29 July 1981. STR/AFP/Getty Images