"That was a very symbolic moment, because the queen only ever bowed her head for heads of state," said Brown. "[It] was a huge personal recognition of hers, that she must do this thing which, for her, went against the grain — acknowledge that Diana's death was commensurate to the death of a head of state."
"It was a very big thing for the queen to do. I think if she had not done it, the crowd would have gone absolutely crazy."
Some thought they already had. Peter Morgan, the Oscar-nominated screenwriter of "The Queen," said, "I didn't recognize my country. ... This seemed like a deranged emotionality. People ... came down with children from the north of England. They made no arrangements about where to stay. ... My sense is that Diana has been revised downward by history, and she is seen in England now as just sort of a troubled and complicated woman."
Brown disagrees. "She was troubled, she was neurotic, but the thing is that her positives so outweighed the negatives that those are the things that survive her life," she said. "What's left are those images of her embracing a child with AIDS, walking a mine field, holding the hands of leper patients. These are the things that live on, long beyond the other stuff."
And if she is correct, if Diana's legacy of compassion lives on, has she in some way changed the monarchy, itself?
"I think that Diana actually helped shake the royal family into the 21st century. She was the engine of change. She was a cataclysmic force, a meteor that landed on them and forced them to change their ways," said Brown.
"They've come to realize that the palace has to respond — that was the major thing that Diana had a beef with. She said, 'Terrible things happen, and where are we? If a bomb goes off in Ireland, you want to be there.'"
And when the bombs went off last July in London, the queen was there.
"She went right to the victims, visited them, gave an impromptu speech at the hospital, bowed her head with the rest of her staff about in the courtyard of Buckingham Palace," said Brown. "Her aide said to me, 'We would never have done this in the years before Diana.' ... The tragedy is that it took her death for the palace to listen to her, and that's, I think, the very saddest thing."
If Diana was able to speak to her legacy, she would no doubt point to her two sons.
"She really taught William and Harry with her loving mother's touch to be first, boys, and then princes — not stuffy, not stuck up, not isolated," said Brown. "They've developed into very attractive young men."
Brown calls Diana "the greatest thing to happen to the monarchy since Queen Victoria."
"She was the ultimate star of the 20th century monarchy. We'll be talking about her for the next 50 years."