For more than 70 years, the Queen has been a steady hand steering the monarchy through wars, political upheaval and civil unrest.
Her reign is often summed up in one word: stability. Her strength and constancy are inextricably tied to the monarchy.
But with Queen Elizabeth II performing only "light duties" after testing positive to COVID-19, that symbol of fortitude has been put to the test.
Since a brief hospital stint in October, the Queen's health has been under greater scrutiny than ever before.
In seeming acknowledgement of this, the palace went to great lengths after her COVID diagnosis to reassure the public that she is still very much in charge, continuing to work in isolation.
On one level, this might simply be the desire of the Queen to reassure an anxious public that she is still fit to govern.
But the necessity of such platitudes also reveal fissures in the foundation of the House of Windsor, observers suggest, as well as an uncomfortable truth.
The stability of the monarchy still rests on the shoulders of the Queen alone.
Why the Queen may be reluctant to hand over duties
The duties of a queen are myriad and complex. Sometimes it is providing a balm for a struggling nation with a gentle wave or thoughtful speech. At others, it's reading through the varied affairs of state.
Queen Elizabeth II also serves as a role model for her people and her commitment to her job as monarch is one of the hallmarks of her reign.
But she does not work alone. Indeed, Prince Philip's tongue-in-cheek nickname for the royal family as a "Firm" suggests the monarchy operates more like a business than a one-woman show.
There is of course an army of staff who work behind the scenes to help keep the monarchy ticking along — private secretaries, communications advisers, heads of households and countless others.
And then there's the wider family: The Queen's sons, daughters, grandchildren and great-grandchildren.
As royals, they can support the monarch with her ceremonial duties — cutting ribbons, attending public engagements and embarking on tours abroad.
But she says the Queen has been resistant to hand over the duties she believes should only be carried out by a monarch.
"What's really interesting is in this current episode of ill health, as with previous episodes of ill health, the Queen has really resisted actually formally handing over the role," she said, adding that the last time the Counsellors of State were called in was when the Queen was overseas in 2015.
"That's the last time to my knowledge that's happened, which indicates that the Queen has actually retained all those official monarchical duties."
Observers say the Queen may simply desire to fulfil the commitment she made at 21 years old, in which she pledged to devote her life to the role.
But it does raise questions over what the future holds for her heir, Prince Charles.
The tense relationship between monarch and heir
History is littered with examples of the tense relationships between reigning monarchs and their heirs.
Take a look at Queen Victoria, who was until recently the longest-reigning monarch in British history.
As she spent decades on the throne, her son and heir, Albert Edward, Prince of Wales, struggled with the confines of his role as next in line and pushed for more duties.
"He argued repeatedly throughout his adult life that he should have a more visible role in matters of state, but his mother thought otherwise and didn't even let him see the official papers of state," Giselle Bastin, royal expert and associate professor of English at Flinders University, told the ABC.
While he eventually became king at the age of 69, he only ruled for a decade.
The dynamic between the head of state and the next-in-line is also fraught because of the very nature of succession, Ms Bastin says.
"Notwithstanding the long wait for the throne, the dynamic between sovereign and successor is made even more complicated by the fact that accession to the throne is usually only made possible by the death of [usually] the heir's mother or father."
But while the role of monarch is a lifetime commitment, there are some measures in place to assist the Queen should she be unable to fully carry out her duties.
The tension between family and the 'Firm'
As heirs to the throne, Prince Charles — and to a lesser extent Prince William — has stepped up as the Queen has suffered bouts of ill health.
It's also understood that Prince Edward's wife Sophie Wessex and Catherine, Duchess of Cambridge, have provided assistance to the Queen in the past.
But the constitution provides the monarch with the option of leaning on an intimate circle of adult heirs, dubbed the Counsellors of State, if she were unable to carry out her duties in full, Craig Prescott, a lecturer in UK constitutional law at Bangor University, told the ABC.
Currently, that group consists of Prince Charles, Prince William, Prince Harry and Prince Andrew.
Of that group of four, one is currently embroiled in scandal and another has left the family and moved to a different country in what is a sign of just how fractured the royal family has become.
Prince Andrew's reputation remains in tatters after recently settling a lawsuit lodged by Virginia Giuffre, who alleges she was sexually abused by him when she was 17.
Meanwhile, Prince Harry moved to the US, having made his displeasure with the confines of the Firm known in an explosive interview with Oprah Winfrey last year.
"It's always just one step away from Shakespeare, isn't it? All of the court dynamics have been the same for centuries," Mr Prescott said.
Only an act of parliament can remove either royal from the role. But the optics and politics around stripping Prince Andrew and Prince Harry of such a position may prove difficult for the palace, Mr Prescott said.
"The politics of it soon looks very messy and so I think everyone is like, 'well, let's put it in the too-difficult pile because you could soon end up in positions that aren't very nice for anyone to be in," he said.
While publicly this would raise eyebrows, personally the stakes are higher for the Queen, who must contend with both her responsibilities as monarch and her duties to her family.
Is it time to retire 'The Firm'?
According to Ms McCreery, recent scandals demonstrate that the idea of "The Firm" no longer fits with how the current royal family operates.
"You only have to look at the situation with Harry and Meghan to see that the idea of a firm doesn't really fit and look at what's happened to Andrew — who's 'The Firm' anymore?" she asked.
Ms McCreery says in place of "The Firm" is a senior group of working royals, which includes Charles and Camilla and William and his family, who are "shielded from as much negative press attention as is possible".
"I think we've seen quite clearly that Andrew and even Harry are really no longer in that sort of circle of trust, if you will," she said.
Privately, however, the royal family's dynamics may be playing out differently to what the public sees.
"I still think that we don't know and can't know what happens at a family level," Ms McCreery said.
She believes the Queen may still regard Prince Andrew as her son and recognises him as a part of her family, even if publicly "he's been hung out to dry".
"I think at a family private level, it may well be that some of what we see as public divisions actually aren't as important and that they can act in a loving family way."
It's likely now more than ever that the monarch's loved ones will be hoping to provide whatever support they can as she recovers.
Yet with the Queen determined to remain at the helm, it will be up to her to continue to chart a steady course for the House of Windsor.
