Prince Philip and Queen Elizabeth have always wanted Prince Charles and Princess Diana together. But when they realized that the couple’s relationship could no longer be repaired, they weren’t able to do anything to fix it.

In the BBC Radio 5 documentary “Images of Diana,” royal author Sarah Bradford said that the Princess of Wales was quite close to her father-in-law. In fact, the Duke of Edinburgh exerted the effort to make sure that Princess Diana wouldn’t feel left out.

“It’s not been realized how supportive the Queen and Prince Phillip were to Diana when she was going through all this [marital trouble]. The Duke of Edinburgh called himself ‘pa’ to her, and he wrote supportive letters saying ‘Charles’ behavior is awful.’ He really wanted to keep things together and so did the Queen…They didn’t like Camilla and Charles carrying on a relationship which endangered the monarchy,” she said.

In the book “The Diana Chronicles,” royal author Tina Brown said that Princess Diana and Prince Philip’s relationship was quite complex. There were times wherein the late royal would write about how angry, unpleasant, and raging Prince Philip was to her when talks about her and Prince Charles’ separation first came to light.

And according to Brown, the mom of two was also outraged by some of the letters that Prince Philip wrote to her even though his intention was to counsel her.

“Charles, Philip told her, had ‘made a considerable sacrifice’ in cutting ties with Camilla, and the Princess ‘had not appreciated what he had done,’” Brown said. And on one occasion, Prince Philip seemingly blamed Princess Diana for Prince Charles’ infidelity.

“Can you honestly look into your heart and say that Charles’ relationship with Camilla has nothing to do with your behavior towards him in your marriage?” he wrote in his letters to Princess Diana.

But in the end, Prince Charles and Princess Diana’s marriage still ended in a divorce. And Prince Charles still married his former mistress, Camilla.

Prince Philip, Queen Mother, Princess Diana, Queen Elizabeth, Prince Charles, Prince William Pictured: Prince Philip, Prince Charles, Queen Mother, Princess Diana with Prince William and Queen Elizabeth II at Buckingham Palace. Photo: Getty Images/PA