Historians love umbrellas, though not the sort you see blown inside out by the wind and stuffed into bins. These ones are different: names which can be used to define, categorise, delineate and otherwise organise the societal, technological and political characteristics which mark an era. Coat pegs you can hang things on. One word Pinterest boards you can plaster with, say, mental images of men in top hats or women in tweeds riding Penny Farthings.

On our tiny plot of land above the 55th parallel we’re quaint enough to still use the names of our monarchs to mark the passing of time and trends. Leaving aside pernickety disputes over numbering protocols we generally know what people mean when they say Edwardian, Georgian, Victorian or Elizabethan. They mean, respectively, clipped moustaches, Jane Austen novels, flushing toilets and either the entry into our national cuisine of the humble potato or the last known sighting of the codpiece as a serious fashion item.

What was known as the New Elizabethan Era ended with the sad death of Queen Elizabeth II at Balmoral on Thursday. It was an era marked more by change than by coherence. Both Mao Zedong and Harry S Truman were still in power when she assumed the throne, the so-called Age of Deference still had a decade to run and the world was one of binaries – East versus West, Communism versus Capitalism etc. Today, Chinese tourists pay to wander the halls of Buckingham Palace, we all have computers in our pockets (though few of us carry cash), and the late Queen’s life has been turned into a warts-and-all TV drama you can stream over the internet and watch on a smartphone wherever you are in the world.

Oh, and binary has acquired a prefix and means something else entirely.

Enter King Charles III, who 46% of Britons thought should abdicate immediately in favour of Prince William on becoming king according to a 2019 poll. So what sort of monarch will he be once Operation Golden Orb has been enacted and his coronation has passed into British history? How will he write himself into the country’s story? Will it be business as usual for 'The Firm' or is there an envelope-pushing manifesto in a drawer somewhere?

He may be more radical than his mother but I doubt he can be as popular. She was just 25 when she became monarch, the same age as England women’s football captain Leah Williamson, one of those paying their respects last week. The late Queen lived a long life, was unswerving in her diligent approach to her duties and was greatly admired as a result. You only earn those props by putting in the hours. As sovereign, Queen Elizabeth clocked up over 600,000.

King Charles turns 74 in November and is the oldest new monarch to ascend the British throne. The last Prime Minister – sorry, the name escapes me – loved to trumpet the skills of the UK’s life science sector and his part in their success at cooking up a Covid-19 vaccine. But even the most heroic efforts of the Jenner Institute and the Wellcome Trust can’t extend King Charles’ reign beyond his natural life span. He cannot hope to match his mother’s 70 year rule. The clock is ticking. The legacy-building starts now. If legacy is his wish, he needs to be a king in a hurry.

And remember Queen Elizabeth came to the throne already a much-admired daughter of the nation. “Now we can look the East End in the eye,” she famously said after Buckingham Palace was hit by high explosives in 1940. She was 14 then. A year earlier she had made her first radio address to the UK’s children and at 16 she rolled up her sleeves to dig for victory on an allotment. In 1944, aged 18, she joined the Auxiliary Territorial Service as a second subaltern.

King Charles III is a father of two, a grandfather five times over, and a widower now remarried. So yes, he has quite a back story and (as much as you can when your home is a palace staffed with servants) a great deal of what these days we call lived experience.

But in the past he has been belittled or ridiculed – too often, perhaps, for him to be convincing in his new role. He can rightly howl ‘I told you so’ from the rooftops of whichever home his black Range Rover draws up outside, but for years he was mocked for his long-standing interest in environmentalism and dismissed as a ‘tree-hugger’ who talk to flowers. Then, in the lurid tabloid psychodrama his marriage to the Princess of Wales became, he went from weirdo to villain, often cast as cold, unfeeling, scheming. An adulterer by his own admission (this in a 1994 television interview with Jonathan Dimbleby). The cultural beatification his late wife underwent following her tragic death in 1997 didn’t help his public image.

The criticism didn’t end there, either. As Prince of Wales he had – and as king presumably still holds – strong opinions on everything from modern architecture (loathes it) to alternative medicine (likes it). His interventions on these subjects were often made on public platforms and just as often brought damning put-downs from the self-appointed guardians of culture and ‘taste’. No wonder he once described himself as a “dissident”.

And who can forget the so-called ‘black spider memos’, letters from him to British government ministers which were only released after a lengthy legal battle? They brought to his door allegations of meddling in politics. “I’m not that stupid. I do realise it’s a separate exercise being sovereign,” he said in a 2018 BBC interview. “The idea that somehow I’m going to carry on exactly in the same way is complete nonsense.”

History tells us kings named Charles don’t have an entirely happy history on these isles. Charles I had his head removed by order of Parliament in 1649, the culmination of an internecine struggle much referenced and re-examined in the constitutional and parliamentary ructions following the 2016 Brexit vote. His son became Charles II after the restoration of the monarchy in 1660 and was, according to volume two of my Ladybird book of kings and queens, “witty, amusing and popular”, “one of the cleverest kings ever to occupy the English throne” and a man who “enjoyed music and dancing and encouraged the new theatres in which, for the first time, women appeared on the stage.”

That augurs well, at least. Perhaps Charles III sees himself as an echo of that sovereign. However Charles II also had an epidemic to deal with – bubonic plague killed around a quarter of the population of London in 1665 – and then a year later the Great Fire of London, which did for the built environment what the Yersinia pestis bacterium had done for its occupants. Pick whatever historical resonance you like out of that lot.

So what are we going to get from our new sovereign? Charles the Wise, will that be his shtick? Charles the Good, perhaps? Can Charles the Meddlesome stay in his box?

David Attenborough in ermine would be a good look. A moderniser, a king with the imagination and vigour to overhaul the monarchy, to slim it down in terms of personnel while ramping up its purchase on and importance to young, multicultural Britain. We wait and hope.

‘Stands Scotland where it did?’ Macduff asks Ross in Shakespeare’s Macbeth, written (probably) to celebrate the Stuart accession to the throne in 1603. ‘Alas, poor country, almost afraid to know itself,’ Ross replies. For Scotland back then read the UK now: adrift in Europe, sinking in debt, troubled by culture wars. A country riven, rudderless, divided and depressed. Can a new monarch sort that out? Is there a story he can tell which can unite us all?

Call the new era whatsoever you like – Carolean is the not-exactly-snappy umbrella term historians could use if they so choose – but it’s a hell of a big ask. Even of a king.