They were married for a staggering 73 years, so when Prince Philip died last year, many wondered how Her Majesty would carry on.
She did for a bit, but ultimately the longing proved too much, says Katie Nicholl, a royal expert and author of The New Royals: Queen Elizabeth’s Legacy and the Future of the Crown.
“She was never the same after Philip went. I think she ultimately died of a broken heart really. He was, she said, her strength and stay. He supported her in everything she did in life.”
The 96-year-old monarch now lies alongside her late husband in the King George VI memorial chapel – part of St George’s chapel in Windsor Castle – after passing away peacefully on 8 September.
Buckingham Palace released a photo displaying the newly inscribed marble slab that was laid into the floor following the queen's state funeral on 19 September. It shows the names of the late monarch, her husband and parents, along with their dates of birth and death.
Between the two couples is a single metal Garter Star, the insignia of the Order of the Garter, the country’s oldest and most noble order of chivalry.
All four were members of the order and St George’s Chapel, where the memorial chapel is situated, is its spiritual home.
The humble stone annexe, which can be viewed through a metal gate inside St George’s Chapel, also contains the ashes of the late monarch’s sister, Princess Margaret.
The public will be able to view the queen’s final resting place but will have to pay for the privilege.
Nicholl also claims in her book that the queen was left "hurt and exhausted" by Prince Harry and Meghan’s decision to step down as working royals and move to the US.
The author cites a source close to the queen as saying she didn't like to think about the Duke and Duchess of Sussex’s decision to leave the family.
She was also reportedly disappointed when the couple didn’t return to the UK in August with Archie (3) and Lilibet (16 months) for the annual "sleepover" the queen hosted at her Sandringham estate for her grandchildren and great-grandchildren.
The source is quoted as saying, “The queen was very hurt and told me, ‘I don’t know, I don’t care, and I don’t want to think about it anymore’.”
Nicholl also claims one of the reasons Prince William was so angry about the Sussexes’ decision to quit The Firm is because of the extra strain it would place on his family.
“It was William who felt Harry's departure most acutely because of the immediate repercussions on his own life,” Nicholl explains in the book.
“Friends of his say one of the reasons he won't forgive Harry is due to the consequence of Megxit for Kate and their children.
“The Cambridges now have a significantly increased royal workload while trying to raise their young family.”
Sources: dailymail.co.uk, honey.nine.com.au, Instagram