The Queen bravely continued to fulfil her duties in her final days despite battling mobility problems in recent months and a series of health setbacks in previous years.
The 96-year-old monarch, who passed away peacefully on September 8 at Balmoral Castle in Aberdeenshire, had been determined to appoint Liz Truss on Tuesday as her 15th Prime Minister.
The historic audience took place at Balmoral, instead of Buckingham Palace as tradition would normally dictate, after royal doctors advised her not to travel, for her comfort. Her Majesty had been utterly determined to carry out the engagement.
But despite displaying a broad smile she appeared frail, leaning on a walking stick with visible bruises on her hands and swollen ankles.
A gruelling schedule of appointments that day, including ploughing through her ministerial red boxes, led her to pull out of an important Privy Council meeting 24 hours later.
The Queen was due to appear via video call at the session to witness Ms Truss take her oath as First Lord of the Treasury - the PM's official title.
New Cabinet ministers would also have been sworn into their roles - and made Privy Counsellors if not already appointed as one in the past.
Royal sources suggested the Queen had appeared incredibly tired after an unusually busy day.
She met outgoing Prime Minister Boris Johnson, new PM Ms Truss - and also invested her outgoing communications secretary Donal McCabe with the Insignia of a Lieutenant of the Royal Victorian Order, an honour in the monarch's personal gift for service to the Royal Family.
A number of guests were seen leaving the castle even before the first audiences began.
Until Tuesday, the Queen had not been seen in public since July 21, when she disembarked a private jet at Aberdeen airport for the start of her summer holiday in the Highlands.
But she missed the traditional welcome ceremony at Balmoral - where she would normally meet wellwishers - after experiencing a flare-up of her mobility problems.
Her issues getting about had also resulted in her pulling out of a series of key events in her diary, including last weekend's Braemar Gathering, the Highland Games sporting occasion which she only missed six times in her 70-year reign.
Her son, the new King Charles III, stepped in for her on that occasion.
Despite her battles, the Queen thrilled crowds on the first day of her Platinum Jubilee celebrations on June 2 when she appeared on the Buckingham Palace balcony and later at Windsor Castle.
But the next day she pulled out of the Platinum Jubilee Service of Thanksgiving at St Paul's Cathedral after experiencing "discomfort" during the previous day's celebrations.
The decision was considered regrettable, it is understood, but sensible due to the length of the journey and time involved and the physical demands it would have entailed.
She had fulfilled a number of in-person engagements in the weeks leading up to her Jubilee celebrations.
They included a surprise appearance to officially open the Elizabeth line at Paddington Station, looking bright and cheery - though her visit was limited to 10 minutes.
She also turned up at the Chelsea Flower Show and was driven around the floral extravaganza in her new hi-tech golf buggy for comfort. They were welcome public appearances for a monarch who, in October last year, used a walking stick at a Westminster Abbey service - the first time she had done so at a major engagement.
A week later, after a busy autumn programme, she was ordered to rest by her doctors and advised to cancel a trip to Northern Ireland.
On October 20, the Queen was secretly admitted to hospital for "preliminary investigations" and had her first overnight stay in hospital for eight years.
The next day she was back at her desk at Windsor, carrying out light duties.
But concern for her health mounted when she pulled out of more high-profile engagements, including the Cop26 climate change summit and the Festival of Remembrance, with Buckingham Palace saying she MEMORIAL had been advised to continue to rest and not carry out any official visits.
She was intent on attending the Remembrance Sunday service at the Cenotaph, but missed this poignant event due to a sprained back.
For more than three months she carried out only light duties, including virtual and face-to-face audiences in the confines of Windsor Castle. In February 2022, she celebrated her Platinum Jubilee, meeting charity workers at Sandringham House, Norfolk, and cutting a Jubilee cake in what was her largest in-person public engagement since October.
At every point, the Queen appeared as cheery as ever - though, clearly, the workload was taking a toll.
Many of her most recent duties were carried out via video calls.
And Britain's longest-reigning sovereign famously remarked during one in-person audience in February: "Well, as you can see, I can't move."
There were further fears for her health when she caught Covid, testing positive on February 20 this year.
The triple-vaccinated Queen suffered from mild cold-like symptoms but said the virus left her "very tired and exhausted".
She carried on with light duties while self-isolating at Windsor but cancelled some virtual audiences.
Her Majesty pulled out of the Commonwealth Day service at Westminster Abbey in March, a significant date in the royal calendar given the importance to her of the family of nations, and did not attend the Maundy Thursday service either.
But she rallied to honour her late husband the Duke of Edinburgh at a memorial service at the end of March, walking slowly and carefully with the aid of a stick, and holding on to the Duke of York's elbow for support.
In May, she missed the State Opening of Parliament for the first time in nearly 60 years, with Buckingham Palace attributing her absence to "episodic mobility problems".
The Prince of Wales and the Duke of Cambridge opened parliament on her behalf as Counsellors of State, with Charles reading the Queen's Speech for a historic first time.
Much has changed in the past seven months, with Buckingham Palace mostly only confirming the Queen's attendance at engagements on the day, with the decision dependent on how she is feeling in the morning.
She did go to the Windsor Horse Show - another of her favourite events - in May. And she was also the guest of honour at the equestrian extravaganza A Gallop Through History near Windsor, the first major event of the Jubilee festivities.
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