When Buckingham Palace said Queen Elizabeth won't be going to Sri Lanka for a Commonwealth meeting this fall, the decision was more than a reflection of how a robust but aging monarch will be taking things a little bit easier after 61 years on the throne.

Opting out of the Commonwealth heads of government meeting and having her eldest son, Prince Charles, attend instead gives him a high-profile role and suggests that the 87-year-old Queen is helping him prepare for his eventual role as king.

Charles has stepped in to represent the Queen in the past, and more frequently in recent years. But attending the Commonwealth heads of government meeting would be one of the more significant roles, particularly because being head of the Commonwealth is not a hereditary positon and he would likely be seen as signalling his interest in taking it on.

This move comes as the Queen has "carefully prepared her children for public duties and Prince Charles for his future role,' says Carolyn Harris, a Toronto-based royal historian and blogger. But no one is suggesting at this point that Elizabeth has any intention to abdicate in favour of her son, as the Dutch Queen did last week.

Along with the announcement Tuesday that the Queen will miss the meeting in Sri Lanka, Buckingham Palace said it is reviewing long-haul travel for the Queen and her husband, Prince Philip, who turns 92 in June.

"Really the crux of the matter is that this is all to do with the toll that long-haul journeys take on elderly people," royal commentator Rafe Heydel-Mankoo said in an interview from London.

"What we have seen in recent years is an effort to try to ensure that there's a smooth transition to Prince Charles.… If anything is to be read into it, it's really also part of the deliberate effort to make sure that the public are more used to him taking on these functions."

The decision for the Queen to opt out of the summit in Sri Lanka, the palace also noted, has nothing to do with the political situation in the country, which has been widely condemned by many in the international community over alleged human rights abuses.

"The Queen's devotion to the Commonwealth would never let her become politically partisan in any way," says Heydel-Mankoo.

That devotion has been a priority throughout her reign. She's been at all the heads of government meetings except the inaugural session in Singapore in 1971 — her first appearance was in 1973 in Ottawa — and Harris says her attendance has been seen as significant.

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Queen Elizabeth, Prince Charles and Camilla, the Duchess of Cornwall, are seen before the Queen's Banquet for the Commonwealths Heads of Government in Kampala, Uganda on Nov. 23, 2007. (Ian Jones/Associated Press)

In 2011, in Perth, Australia, for example, "when succession reform was discussed, her presence … was seen as an endorsement of the succession reform and the introduction of absolute primogeniture so that the Duke and Duchess of Cambridge’s first-born child, whether a boy or girl, would succeed to the throne," says Harris.

Charles has been at one meeting, attending that 2007 session with his mother.

"Now with the Prince of Wales attending this meeting, that's also being interpreted as highly significant because the role of head of the Commonwealth is not automatically hereditary," says Harris.

"So the Prince of Wales' increasing involvement with the Commonwealth heads of government is demonstrating his interest in the institution and suitability to be the next head of the Commonwealth."

Charles became heir to the throne at age three, and has been waiting longer than anyone in British history to receive the crown.

Longtime royal watcher Ninian Mellamphy says it "must be kind of tough on Charles when you consider he's old enough to retire and he hasn't actually come into his domain yet."

In helping prepare Charles for his role as king, Elizabeth is taking an approach that differs considerably from the way in which the last long-serving monarch set up her eldest son for the throne.

"It's a marked contrast to Queen Victoria's approach," says Harris, who noted Victoria had "a very difficult relationship with her eldest son, the future Edward the Seventh, and really excluded him from any situation where he would be seen as representing her."

Public expectations were low when Edward came to the throne in 1901.

"He was seen as an idler who had mistresses, who went to the races. But he actually carved out a diplomatic role for himself," says Harris, and by the time he died nine years later, there was significant public mourning.

"He was very well-regarded, but in 1901, there were real concerns that the 60-year-old Edward the Seventh would be able to step into his mother's role. This happens whenever there's a very long reign that the monarch becomes synonymous with the office and it's difficult to imagine anyone else in that role."

While the Queen may be giving Sri Lanka and any other long-haul travel a pass, there's no indication she's taking a significant step back from a vigorous public schedule in the U.K.

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Queen Elizabeth arrives for the rededication of the newly refurbished Temple Church organ at Temple Church in London on May 7, 2013. (Anthony Devlin/Associated Press)

"It's very much business as usual. The Queen is going to continue taking on as many duties as she has in the past," says Heydel-Mankoo.

"Last year, she took part in over 400 engagements and when you think most people would have retired 20 or 25 years earlier, that's a pretty impressive achievement."

Many of those engagements were part of the Diamond Jubilee celebration marking her 60 years on the throne. That celebration, however, also revealed significant hints of an international retreat in Elizabeth's activities, as her children and grandchildren fanned out on Jubilee trips throughout the Commonwealth.

"That really sent the first signal that we had that she would be restricting her long-haul trips," says Heydel-Mankoo, who noted there's no sense yet that the Queen will not be making any return visits to Canada.

Prince Philip himself returned to Canada for a two-day visit late last month, a trip that came as something of a surprise.

"One of the reasons Prince Philip's visit to Canada in April attracted so much attention was that he was undertaking an overseas visit, whereas during the Diamond Jubilee both the Queen and the Duke of Edinburgh had remained in the United Kingdom while their children and grandchildren travelled to the Commonwealth realms," says Harris.

While the Queen may be easing up on some of her royal duties, there is no sense she would ever abdicate, as the 75-year-old Dutch Queen Beatrix did last week, in favour of her eldest son, Willem-Alexander.

"In contrast to the Netherlands, where abdication is an accepted custom, there's a public celebration where one monarch abdicates and the new one comes to the throne, in the United Kingdom and the Commonwealth, abdication is viewed as a destabilizing event," says Harris.

"The Queen vowed on her 21st birthday on her first Commonwealth visit to South Africa that she would devote her whole life, whether it was long or short, to the service of her people and she shows every sign of fulfilling that vow."