At Prince Philip's funeral, the photograph of a lonely Queen dressed in black and wearing a face mask became an indelible image of her long reign.
Secluded inside St George's chapel, the monarch stoically sat a safe distance away from the rest of her family — her four children and eight grandchildren — observing the COVID-19 restrictions in place at the time.
The scene drew an outpouring of sympathy for the Queen, reminding the public that the powerful leader was also a grieving widow just like any other.
Now, a year after her husband's death, with so many family stresses and health issues at play, the Queen is reportedly extremely conscious of avoiding another iconic image at his memorial later today.
In the lead-up to the service to commemorate him, some royal reporters suggest a meticulously orchestrated military-style plan will be enacted to get her into Westminster Abbey without photographers getting a picture of her using a wheelchair.
It comes amid more scrutiny of the Queen's health than ever before, after a recent COVID-19 diagnosis and the cancellation of some public events.
While mobility issues are to be expected for a woman of her age, the Queen's role as head of the Commonwealth means that such conjecture has "wider political implications," observers suggest.
History has not been kind to ageing monarchs
The Queen's recent ill health has drawn comparisons with the final months of her beloved sister, Princess Margaret.
Margaret's personal life received a great deal of scrutiny, and her health problems mounted as she grew older and her lifestyle took its toll.
Paparazzi scrambled to get photos of her out in public as the tabloid press speculation about her mortality reached a fever pitch.
The result was that Margaret was cast as an increasingly frail figure in the final years of her life, according to royal commentator and historian Carolyn Harris.
"Her decline was very evident to the public, and so it attracted some public interest and some public sympathy," she said.
History is littered with examples of royals who have experienced increasing pressure and scrutiny as they advance in age.
There was a great deal of concern among the court of King George III as his mental health failed in his final years, for example.
And one of the indelible images of Queen Victoria's reign is of an elderly, austere monarch, dressed in black with a haunted expression.
In her later years Queen Victoria also struggled with mobility and took part in public ceremonies from her carriage after being unable to climb the stairs of St Paul's Cathedral.
"It would have been clear to the public that Queen Victoria was growing older and having these health issues," Ms Harris said.
But while history has not been favourable to monarchs in their final years, in modern times there is more awareness of the prejudice behind such speculation.
Privacy vs the public's right to know
Images of Princess Margaret using a wheelchair in the final months of her life have been described as "undignified" and "haunting" by some British commentators.
"That was awfully embarrassing, if you remember," said entertainer Chris Biggins on the GB News breakfast show.
But disability advocates say such language reinforces the belief that disabilities are something to be hidden from public view.
"Nobody should feel such internalised ableism that they are actively doing more work and causing themselves stress just in order to not be seen with tools that make their lives easier," Rachel Charlton-Dailey wrote in Metro.
The debate has once again revealed the tension that has always existed between the monarch as a human being and as a head of state.
The woman who wears the crown is grappling with issues that eventually affect us all: Mortality, ageing and privacy.
And she has a right to decide what she shares of herself with the public.
The Queen and her aides, however, appear keenly aware that the British monarchy is in a period of transition.
Any photo that shows the Queen's reduced mobility will serve as a reminder that the second Elizabethan era will not last forever.
The House of Windsor's next generation faces an uncertain future.
Last week, Jamaica's Prime Minister told Prince William that he will probably never be the Caribbean nation's head of state.
And with the Queen's son Prince Andrew planning to attend his father's memorial service, there is another potential photo opportunity stiring public interest.
Prince Andrew is on the guest list
The confirmation that Prince Andrew will attend, just a month after settling a lawsuit with a woman who had accused him of sexual assault, has also raised eyebrows.
The concern is whether the Duke of York's attendance will distract from the event, given the well-publicised case and his association with notorious paedophile Jeffrey Epstein.
Will he be content with being quietly supportive of the Queen in his capacity as her son, or will he try to gain public attention?
Observers point to Prince Andrew approaching the media to eulogise his father last year as one possible clue.
"While that was in a personal capacity, there was a sense that he was trying to move into a more public role," Ms Harris said.
"So I think there will be scrutiny of whether he is simply quietly there at this event, or whether he appears to be trying to gain some kind of public attention, as it's very clear that he will not be returning to public life after his recent circumstances and legal settlement."
While Prince Andrew has been stripped of his military titles and royal patronages in response to the scandal, his presence at the event confirms that he cannot be erased from the House of Windsor.
Preserving the Queen's 'strength and stamina'
Queen Elizabeth II earlier this year marked an unprecedented milestone of 70 years on the throne.
After decades of serving Britain and the Commonwealth as monarch, she also renewed a pledge she first made at 21.
"In this year of my Platinum Jubilee, it has given me pleasure to renew the promise I made in 1947, that my life will always be devoted in service," she said.
But the reality is that the Queen is "unlikely to ever undertake hours of investitures again", according to British media.
"The Queen's workload has been 'under review' as palace aides work with royal doctors to ensure that she paces herself, ahead of a series of events to celebrate her historic 70 years on the throne this summer," The Telegraph reported.
The Queen has been undertaking light duties since recovering from COVID-19 and has missed some public events, such as the Commonwealth Day services earlier this month, due to concerns surrounding her mobility.
The recent focus on the Queen's virtual video conferences may be the palace signalling that the monarch is still very much active in her role as head of state, according to historian Carolyn Harris.
But advisers will likely also be mindful of the Queen's condition and the number of commitments she will be expected to attend during her Platinum Jubilee year, Ms Harris says.
There is clearly a "very strong emphasis" on preserving her stamina and energy for these events, she adds.
"There's some efforts to ensure as much as possible that the Queen is able to participate in the ceremonies as this is a very big historic milestone in her reign," she said.
While work is being done to ensure the Queen is comfortable and able to continue her duties, the monarch is doing so with the eyes of the world watching her.
After more than seven decades on the throne, Queen Elizabeth II is facing one of her biggest tests yet.
