Queen Elizabeth has been leading the monarchy for decades. During her time as Queen, there are two tragedies that she regrets the most.

In the book “The Firm,” royal biographer Penny Junor said one of the Queen’s biggest regrets had to do with her visit to Aberfan in 1966.

“The Queen is said to regret her delay in visiting Aberfan in 1966, recognizing in hindsight that it was a mistake not to be there immediately to comfort the grieving and express her sorrow,” he said.

During that time, a colliery spoil tip collapsed, and it killed 116 children and 28 adults.

According to Junor, the Queen’s second-biggest regret might have something to do with Princess Diana. After the Princess of Wales’ died, the Queen focused too much on the welfare of her two grandchildren, Prince William and Prince Harry.

This resulted in royal fans thinking that she didn’t care about Princess Diana’s death.

“I suspect she regrets her instincts during that week after Diana’s death, too. Her first thoughts were for her grandchildren, and for once she put family before duty… It was a mistake, however, to let the nation believe that neither she nor any other member of the Royal Family cared about the tragedy that had pole-axed the nation,” Junor said.

According to the royal biographer, Her Majesty misjudged the entire situation. The Queen spent her days in Balmoral and the public didn’t see her until days after Princess Diana’s death.

And since the Queen locked herself away from the public, she didn’t have any idea how the royal fans were feeling after Princess Diana’s shocking demise. Thousands of people flocked the streets of London to pay tribute to the Princess of Wales.

“She thought that the answer to the mass hysteria was to stay calm and to keep on doing what the family had always done, safe in tradition,” Junor said.

Princess Diana passed away on Aug. 31, 1997, following a fatal car crash in Paris.

Queen Elizabeth II
Queen Elizabeth II is seen at the Chichester Theatre while visiting West Sussex on Nov. 30, 2017, in Chichester, United Kingdom. Getty Images/Stuart C. Wilson