After such a protracted apprenticeship, many will ponder how long he may reign over us - a question not only of the 73-year-old King's own longevity but of his subjects' taste for independence.

If Charles replicates the life span of his mother - who died on Thursday aged 96 - he will likely rule for the next two decades, unless republican sentiments resurface with greater unity than they did in the 1990s.

Charles has never enjoyed the popularity levels of Elizabeth II, but generally seems to have been liked well enough, ever since Aussies got to know him first-hand in 1966 as a painfully shy teenager attending Geelong Grammar's elite but tough "finishing school" Timbertop.

"I have gone through my fair share of being called a Pommy bastard, I can assure you of that," he recalled of his student days to roars of laughter in a 2011 speech in London.

"But look what it has done for me. By God, it was good for the character. If you want to develop character, go to Australia."

Charles's character has been called into question several times during the intervening years, never more so than during the painful break-up then divorce from his first wife, Diana, and her death in a Paris car crash a year later.

Aussies, ever keen on egalitarianism, were always willing to give him the traditional fair go, with the early illegitimate tag used as a mark of affection.

As he grew into adulthood, Aussies came to know him as a free thinker with an interest in architecture and ecology, a tree hugger who talked to the plants, and later, courtesy of the salivating British tabloids and a rogue radio enthusiast, a philanderer who fantasised about being reincarnated as a tampon so he could live inside his then lover and now, quite possibly, Queen of Australia, Camilla.

Over the years Charles has professed a "huge affection" for Australia.

But he is well aware of the history of the republican movement and would know that many advocates have been waiting until the death of his mother to renew the push which failed so spectacularly at the ballot box in a 1999 referendum.

Barbados was the latest Commonwealth country to become a republic in November, 2021; Prince Charles, as guest of honour, witnessed his mother being officially removed as head of state so there's no reason to think he should feel slighted if Australia was to follow suit.

Whether that happens is a matter of conjecture, considering the republican issue has been off the boil for more than 20 years.

Charles certainly has a deep personal knowledge of Australia, having made 16 visits - the same as his mother though six fewer than his father, the late Duke of Edinburgh.

The last time was with Camilla in 2018 to open the Gold Coast Commonwealth Games.

The first time Charles visited Australia in an official capacity on his own - albeit with a valet, equerry and Special Branch police superintendent - was to represent the Queen at the funeral of drowned prime minister Harold Holt in 1967.

His low-key visits in the 1970s were as a bachelor prince, and one bikini-clad girl famously raced out from the surf at a Perth beach to give him a kiss on the cheek.

The best thing to happen for his profile, at least initially, was his marriage to Lady Diana Spencer. On their first Australian visit together in 1983 they brought their baby William, now first in line to the throne, in defiance of the convention that an heir and his successor should not travel together.

They were a smash hit with the public, drawing rock-star crowds wherever they went, including an estimated 200,000 in Melbourne's Bourke St Mall. "Dianamania" was born.

When they performed encores in 1985 and 1988, Australia's bicentenary year, much the same thing happened, leading to reports that Charles was miffed at the way his glamorous wife dominated the media attention.

In his 1992 biography of Diana, Andrew Morton said this drove a wedge between them: "The crowds complained when Prince Charles went over to their side of the street during a walkabout. In public, Charles accepted the revised status quo with good grace; in private he blamed Diana."

If Charles's star rose with Diana, so did it fall with their separation in 1992 and their divorce four years later. The tabloids had a field day reporting extramarital affairs on both sides. Diana, referring to Camilla Parker-Bowles, told BBC television: "There were three of us in this marriage, so it was a bit crowded."

In 1994 a troubled 23-year-old man was arrested after firing a starter pistol at the prince as he prepared to hand out Australia Day awards at Sydney's Darling Harbour.

Then NSW Premier John Fahey distinguished himself by wrestling the attacker to the ground. Charles never forgot, praising Mr Fahey's selflessness and valour in a letter that was read out at his funeral in 2020. "I was as fortunate to have him on my side that day as the people of NSW always were to have him on theirs," the prince wrote.

Charles returned in 2005, shortly before his wedding to Camilla; seven years later they came as a royal couple to mark the Queen's diamond jubilee on a six-day visit which, the press reported, cost Australian taxpayers $437,000.

Much attention has been devoted to whether Camilla will become Queen.

Clarence House insisted on their wedding day she would be known as "Princess Consort", even though under English common law, the wives of kings automatically become queens.

It's now thought she might take the title "Queen Consort", but former courtiers have been quoted as saying Charles will insist on "Queen".

Charles has become more assertive in the political arena, too, on issues dear to him, such as global warming.

He urged Australian Prime Minister Scott Morrison to attend the 2021 climate summit in Glasgow, which the Liberal leader eventually did, saying it could be the world's "last-chance saloon" to avoid "catastrophic" impact to the planet.

Australia's devastating 2019-20 bushfires also worried him, and he imagined the nation had been through "an apocalyptic vision of Hell".

A 2015 poll released by the Australian Republican Movement showed 51 per cent of voters would prefer an Australian head of state to "King Charles" when the time came for him to ascend the throne, with just 27 per cent opposed and 22 per cent undecided.

Former prime minister Paul Keating described Charles in a 2018 interview as a "great friend of Australia" but said he had no doubt Charles believed "Australia should be free of the monarchy".

That is a question Charles can now consider, for the first time, as King.

Australian Associated Press