Just six words in the brief, bald statement from Buckingham Palace really brought the news home. "The King and The Queen Consort", it announced, would be spending the night at Balmoral before journeying to London. Even more than the key statement of Elizabeth II's death on Thursday, these six words told the world that an era had ended.
For 70 years, the British people have grown used to singing "God Save the Queen". To sing "God Save the King" will catch in the throat for some time to come. Flags, coins, banknotes and stamps across the UK will soon look different and senior lawyers who were honored to be appointed "Queen's Counsel" are rushing to order new stationery -- they are "King's Counsel" now.
But the change of sex at the head of the Royal Family goes beyond these cosmetic shifts, with implications for the British monarchy and beyond.
Queen Elizabeth's sovereignty was framed by her gender even before she came to the throne. She was always "Heir Presumptive" rather than "Heir Apparent", since, theoretically, any late-born brother would supercede her. Upon her father's death, her awareness of being a young woman surrounded by older, more experienced men shaped the slightly quiescent, obedient style of her early queenship. Though she would always retain that formidable sense of duty, it wasn't until her later years that Elizabeth II's own strength would come to the fore.
The reversal of gender roles still expected in the 1950s was certainly a problem for her husband. Before the Queen's accession, Prince Philip once said, whatever the couple did was done together, and "I suppose I naturally filled the principal position". He was, after all, an instinctively alpha male with what promised to prove a stellar naval career.
When his wife became queen in 1952, the whole thing "changed very, very considerably", he said. Then, Prince Philip once said to author Gyles Brandreth, he was told simply to "Keep out". There was, by contrast, even discussion in the press as to whether the Queen, as the mother of young children, should really be working at all -- let alone be the world's most prominent career woman.
But for the young Queen herself, there were also advantages to being a woman. Not only could she be cast as a romantic, glamorous figure; she could draw on the memory of her notable predecessors, Elizabeth I and Victoria. As Elizabeth II's first Prime Minister Winston Churchill declared, "Famous have been the reigns of our Queens".
In later decades, she was able to enjoy the role of the nation's beloved grandmother, playfully taking a marmalade sandwich out of her handbag in the Platinum Jubilee skit that showed her enjoying tea with Paddington Bear.
The advantages of her gender for the monarchy itself, however, may have been more profound.
Successive prime ministers have described how helpful they found their weekly audiences with the Queen. Not only was she almost the only interlocutor to whom they could speak openly, without fear of indiscretion or political infighting, she was a uniquely well-informed one.
But her style, it is suggested (for what happened at those audiences was wholly confidential) was never to expostulate -- merely to ask a leading question, or to drop a subtle hint. It sounds, in fact, remarkably like the great British poet William Wordsworth's description of the perfect woman, "nobly plann'd/'To warn, to comfort and command".
A queen, traditionally, has been a gracious, gentle, intercessory figure; endowed perhaps with a quiet strength and wisdom, but essentially passive. True, in earlier days, a queen regnant, like the first Elizabeth -- as opposed to a queen consort -- might take a more active role. With the Spanish Armada on the seas, Elizabeth I declared she had the body 'of a weak and feeble woman', but 'the heart and stomach of a king'.
But Elizabeth I, unlike Elizabeth II, did not only reign over, but rule, her country. The role of a modern constitutional monarch, by contrast, may be one it is actually easier for a woman to fill.
In contrast to a queen, a king, historically, is supposed to be forceful, dominant. Leading armies into battle; hence the spell in the Armed Forces expected of all male Royals! That's a hard act to pull off given that the traditional idea of a king is an image out of tune with the 21st century and what is required of a constitutional monarch.
It is arguably unfortunate that the three next occupants of the British throne (after Elizabeth II) are male -- Charles, William and George. There was for a long time, reservation about seeing Charles III on the throne. Many had sided with his wife Diana in the acrimonious "War of the Waleses"; others felt his outspoken interventions into public affairs would be unsuitable in a sovereign, constitutionally obliged to remain above the fray.
In recent years, his mother did what she could to remedy that. Not only did she allow Charles to take over some of her functions, as her own strength failed but she declared her wish that he should follow her as head of the Commonwealth and, crucially, that his wife Camilla should be known as his Queen Consort. (In deference to the memory of Diana, it was long said Camilla would be merely Princess Consort -- and Elizabeth II knew that for Charles himself to declare the contrary would be an unpopular move.)
Such gestures help -- but they can only go so far to solidify Charles' position. The actor Helen Mirren, who famously played the titular role in the 2006 film "The Queen" once said that while she was raised an anti-monarchist, she was "a queenist". Many feel the same way. Indeed, over the last 70 years, the image of a queen has come to define our vision of sovereignty.
Never an unemotional man --- often accused, indeed of self-pity, or blamed for his adultery --Charles has since his accession taken care to show the warmer side of his feelings; greeting the crowds gathered outside Buckingham Palace, and assuring his subjects, in the speech that followed, he would serve them with 'love'.
King Charles III, in other words, has made a good start. It is important he continue to accept that the feminisation of the monarchy is here to stay.
Sarah Gristwood is a royal historian and broadcaster whose books include Elizabeth: Queen and Crown and The Tudors in Love. The views expressed in this commentary belong to the author.