On 9 September, 2015, Queen Elizabeth II becomes the longest reigning monarch in British history. She surpasses Queen Victoria - and guess what? There is no better way to appreciate Queen Elizabeth than to compare her with her famous, but often surprisingly feckless, forbear.
They were both female monarchs, both enjoyed a Diamond Jubilee, both saw their popularity rise and fall. Both wives and mothers as well as reigning queens; both juggling the requirements of a constitutional monarchy. Both, indeed, asked to perform the difficult balancing act between private life and public duty; to somehow combine a traditional marriage with the requirements of sovereignty...
In preparation for her father's coronation, Princess Elizabeth's governess read her Queen Victoria's account of her own. When she married Prince Philip of Greece in 1947, the courtiers' grumbles about Philip's outsiderness, about the cost of the wedding and- the tensions which meant that even his sisters, married to German princes, were not invited to the ceremony - revived echoes of century before, when exactly the same had been said of Victoria's beloved Albert.
Elizabeth II opened her first Parliament wearing Queen Victoria's crown. From the start, she was compared not only to Victoria but to Elizabeth I - as Churchill put it, 'famous have been the reigns of our Queens'. But Elizabeth became monarch of a country on a very different trajectory.
While Victoria had been lucky enough to preside over the growth of an empire, Elizabeth had to pick her way through the detritus of its destruction. Moreover, in changing times, her deliberate restraint could look like coldness or weakness. By the late Sixties she was described merely as being 'not unpopular' in the country.
But Elizabeth accepted the growing need to sell the monarchy to the people; by contrast, Victoria effectively turned her back on the country. There had from the start of her reign been concerns about her mental stability, and after Prince Albert's died in 1861 she declared her own life over, refusing to attend every event of importance from the meetings of the Privy Council to her own son's wedding party. As her retreat stretched out into not just years but decades, the public's initial sympathy gave way to hostility. 'What do we pay her for if she will not work?', it was asked quite openly.
By contrast, Queen Elizabeth has always been distinguished by the sense of duty that still gives her a punishing schedule of public appearances. 'I have to be seen to be believed', she declared famously. Whatever has happened in the lives of her children (and a difficult relationship with her son and heir just may be one of the things the two queens do have in common), no scandal has touched Elizabeth herself - no equivalent to Victoria's reliance on the ghillie John Brown ('Mama's lover', as her daughters joked), or on her Indian servant Abdul Karim. 'the Munshi'.
Where Victoria caused ructions by repeatedly fighting for what she believed were her rights, lashing out at ministers she disliked, Elizabeth has always operated a deliberately 'hand off' policy. All the same, questions of Elizabeth II's retirement were being mooted as early as 1980; by the end of the decade courtiers had begun to talk about QVS or the Queen Victoria Syndrome, whereby a nation could become tired of an ageing monarch and a parasitic royal family. And that was even before Diana died; the single event which did most to show up the weaknesses in her particular, unemotional, style of monarchy.
But the thing about rock bottom is that the only way to go is up. Perhaps both queens triumphed through sheer longevity, their Golden and Diamond Jubilees celebrated as if the nation itself were cocking a snook at mortality. On 23 September, 1896, Queen Victoria noted in her diary that 'This is the day on which I have reigned longer, by a day, than any English sovereign.'
She won't hold that record for long - but in fact, the later queen may have outpaced the former in a more important way. The first years of the twenty first century have seen the comeback not just of the monarch herself, as happened in Victoria's day, but of the very monarchy.
Whatever mistakes may have been made by lesser members of the royal family, and by those around them, Queen Elizabeth II has emerged as a figure above them - and nothing shows her in a better light than comparisons with her equally durable predecessor. She'll be spending 9 September on a steam train, just as Victoria might have done. Appropriate, since she never shines more that seen in this very specific context of history.