Prince Charles' 'Future Role as King' Was 'Visible' During Platinum Jubilee, Says Royal Historian

LONDON, ENGLAND - JUNE 05: Prince Charles, Prince of Wales and Queen Elizabeth II, Prince George of Cambridge, Prince William, Duke of Cambridge, Princess Charlotte of Cambridge, Prince Louis of Cambridge and Catherine, Duchess of Cambridge stand on a balcony during the Platinum Jubilee Pageant on June 05, 2022 in London, England. The Platinum Jubilee of Elizabeth II is being celebrated from June 2 to June 5, 2022, in the UK and Commonwealth to mark the 70th anniversary of the accession of Queen Elizabeth II on 6 February 1952. (Photo by Hannah McKay - WPA Pool/Getty Images)

Hannah McKay/getty Prince Charles and Queen Elizabeth

Queen Elizabeth's Platinum Jubilee celebrations doubled as a preview of the future of the monarchy in the hands of Prince Charles.

The Queen, 96, limited herself to just a few appearances over the four days of festivities due to her ongoing mobility issues and "discomfort," meaning her heir and son Prince Charles took the lead at multiple events. From taking the salute on horseback at Trooping the Colour to leading the tributes at the Platinum Party at the Palace, Charles was in the spotlight.

"[The Queen] sees this as a great opportunity for the transition to be visible," royal historian Robert Lacey tells PEOPLE in this week's issue.

Adds Sally Bedell Smith, author of Elizabeth the Queen: The Life of a Modern Monarch: "She is in the saddle, but this gets people accustomed to [Charles's] future role as King. There was a feeling of celebrating the past and anticipating the new era."

RELATED: Inside Queen Elizabeth's Decision to Step Back from Jubilee Events: 'She Would Not Want to Stumble'

LONDON, ENGLAND - JUNE 02: Prince Charles, Prince of Wales and Prince William, Duke of Cambridge during Trooping The Colour, the Queen's annual birthday parade, on June 02, 2022 in London, England.Trooping The Colour, also known as The Queen's Birthday Parade, is a military ceremony performed by regiments of the British Army that has taken place since the mid-17th century. It marks the official birthday of the British Sovereign. This year, from June 2 to June 5, 2022, there is the added celebration of the Platinum Jubilee of Elizabeth II in the UK and Commonwealth to mark the 70th anniversary of her accession to the throne on 6 February 1952. ( (Photo by Samir Hussein/WireImage)

Samir Hussein/WireImage Prince Charles and Prince William

Prince William also played a central role in the celebrations alongside his wife Kate Middleton and their three children, taking on a visit to Wales and appearing with his father and grandmother on the Buckingham Palace balcony during Sunday's Platinum Jubilee Pageant finale.

Royal Family
Royal Family

Chris Jackson/Getty

The Platinum Jubilee was also an opportunity for the royal family's relationships to be displayed, like when 4-year-old Prince Louis took a seat on grandfather Prince Charles' lap during the Platinum Jubilee Pageant.

"How utterly charming that was," says a palace insider. "When you consider that he has been said to be a remote parent, to see him do that was charming."

LONDON, ENGLAND - JUNE 05: Prince Louis of Cambridge sits on Prince Charles, Prince of Wales lap during the Platinum Pageant on June 05, 2022 in London, England. The Platinum Jubilee of Elizabeth II is being celebrated from June 2 to June 5, 2022, in the UK and Commonwealth to mark the 70th anniversary of the accession of Queen Elizabeth II on 6 February 1952. (Photo by Chris Jackson - WPA Pool/Getty Images)

Chris Jackson - WPA Pool/Getty Prince Charles and Prince Louis

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The source adds that although it is often said that Kate's parents, Carole and Michael Middleton, are the grandparents they are close to (and they certainly spent a lot of time with them), "it was lovely to see his other grandfather enjoying time with him too."