Lady Diana Spencer was petrified. It was 1980, and she was about to go on a third date with her future husband. The date was a weekend visit to the country home of her future mother-in-law, Queen Elizabeth II. Gulp.

Spencer was not exactly an outsider to the Windsor family, which is the textbook definition of close-knit. Her father served as equerry to the queen — the officer in charge of the royal’s horses. Spencer’s grandmothers were ladies-in-waiting to the queen mother. Spencer had grown up playing with Prince Andrew and Prince Edward.

But now, at Balmoral Castle, Spencer was auditioning to be the future wife of Prince Charles, the heir to his mother’s throne.

Though nervous, as Tina Brown recounted in her 2007 biography of the princess, Spencer knew exactly what to do to impress the outdoorsy family. She went fishing. She rode horses. She let the brisk Scottish wind tussle her hair.

“The Queen found her charming and appropriate,” Brown wrote. “Without fresh-air credentials, Diana would have never got to first base with any of them.”

What happened next — the grand wedding, the dissolution of the marriage, Diana’s untimely death while being chased by paparazzi — has been the subject of countless books, TV shows and movies, the most recent of which is “Spencer,” starring Kristen Stewart as Diana.

Kristen Stewart stars as Princess Diana in "Spencer," a movie that paints a portrait of Diana's time in the royal, public eye. (Neon)

But Princess Diana’s relationship with the queen has always been more difficult to depict and understand, especially because Elizabeth is perennially unable to be reached for comment.

Royal watchers such as Brown have gotten bits and pieces over the years.

By all accounts, the queen initially approved of Diana. Yes, she was a commoner. But she was an upper-class commoner.

“The Prince at this stage was closer to his mother than at any other time in his life,” wrote Ingrid Seward in “The Queen and Di.” “They dined together every evening they were together at Buckingham Palace. The subject of Diana frequently entered their conversation and while the question of his marriage was not addressed directly, by nod and nuance the Queen made it clear that she approved of the young woman she felt she had come to know at Balmoral.”

After marrying the prince, Diana kept her distance from her mother-in-law. She found the queen personable but terrifying. Tensions emerged between Diana and the royal family, including the queen, when their marriage hit romantic and then tabloid troubles. The relationship worsened as Diana suffered from bulimia.

Diana told biographer Andrew Morton that during one conversation with the queen, “she indicated to me that the reason why our marriage had gone downhill was because Prince Charles was having such a difficult time with my bulimia.”

Season 4 of "The Crown" draws on events such as Princess Diana's marriage to Prince Charles and Queen Elizabeth II's relationship with Margaret Thatcher. (Allie Caren/The Washington Post)

“She hung her coat on the hook, so to speak,” Diana continued, according to Morton. “And it made me realize that they all saw that as the cause of the marriage problems and not one of the symptoms.”

Diana kept trying to confide in her mother-in-law. The queen, now 95, grew weary of it all.

One afternoon, Diana stopped by to visit the queen and was made to wait. “The princess,” a palace footman told the queen, according to Seward, “cried three times in half-an-hour while she was waiting to see you.” The queen’s reply: “I had her for an hour — and she cried nonstop.”

In public, even as rumors of the prince’s affairs swirled, Diana was still saying the right things — that the prince supported her, that he was a good father and husband. “That was not what she was telling the queen in their private meetings,” Seward wrote. “Charles, Diana kept saying, was letting down the monarchy.”

The queen couldn’t deal with her daughter-in-law anymore. “Faced with a situation that was slipping out of her control,” Seward wrote, “the queen retreated from the problem and started seeing less of Diana.”

No amount of fishing or horseback riding in the country could save her.

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