Rules of Succession What-Ifs

The recent death of Queen Elizabeth II and the accession of her eldest son King Charles III has rekindled some of my interest in a topic I have never covered on this blog: rules of succession, particularly the alternatives to primogeniture that might be of interest to worldbuilders and royalty buffs alike.

Primogeniture: the plain Vanilla of Succession

The traditional rule in the British monarchy, as in so many others, is male-preference primogeniture, where the eldest son of the monarch takes precedence, but if there are no sons daughters will inherit, i.e. the eldest daughter is in line right behind the youngest son. Quite a few other monarchies historically barred women from inheriting at all, and the most hardcore form of male preference, the Salic law, even males cannot inherit if their claim runs through a female line.

If you ask me having the first-born son inherit it all is milquetoast, and the most milquetoast system of all is absolute primogeniture, where the eldest child inherits without regard for sex, i.e. if the eldest child is a daughter she takes precedence over any younger sons. Oh, lookie lookie, we can show off how equal we all are now! Blech.

A Band of Brothers

A somewhat more interesting system to primogeniture of any sort is agnatic seniority, where the monarch’s younger brothers take precedence over the monarch’s sons. A monarch’s children succeed only after the monarch’s own generation has been exhausted. The only country that currently uses such a system is Saudi Arabia, which after the death of its founder Ibn Saud in 1953 has been ruled by his sons. Yes, his sons rule even now; he had 37 of them (polygyny really helps to boost those numbers…).

Saudi Arabia is an elective monarchy, so various members who would be in line by dint of seniority have been bypassed for various reasons, but agnatic seniority has been the overriding factor. All remaining children of Ibn Saud are in their seventies or eighties, which likely was a driver of the election of Mohammad bin Salman, a grandson of Ibn Saud, to Crown Prince (first in line to the throne). The current king, Salman, is likely to be the last of Ibn Saud’s sons to rule. Still, seventy years is a heck of a run for one generation.

Ultimogeniture: the Youngest inherits!

Far more interesting than any of these possibilities is ultimogeniture, inheritance by the youngest child, not the eldest. Primogeniture tends to be more common due to elder children being able to amass more connections, wealth, power, and privilege with time, but ultimogeniture has proved compelling enough to appear in various contexts. Often it becomes a rule where the youngest child keeps the hearth in their parents’ old age, where elder children have already made their own way and the inheritance isn’t as vital for them, or where the parents’ elder children are already rather aged themselves.

Proximity of Blood: Next of Kin inherits!

Proximity of blood is another approach, where the strongest claim rests with the next of kin; a first-degree relative would trump a second-degree relative, etc., with some other rules used to order the claimants within each of these groups. Proximity of blood is still used as a rule in addition to primogeniture in the Netherlands; succession is limited to those within three degrees of kinship to the current monarch.

What if the British Monarchy used Absolute Primogeniture earlier?

So how would the British succession be different if it adopted any of these rules? The recent change to absolute primogeniture only applies to claimants born after 2011, but in any case wouldn’t change much. Charles is not only the eldest son of Elizabeth II, he’s also the oldest child of either sex. Charles himself only had two boys, no girls. William’s first-born child is a boy, George, but his second-born, Charlotte, was born after the 2011 change, so she’s ahead of her younger brother, Louis, in the line of succession. She’s now third-in-line to the throne, so there is a chance she might become Queen someday.

What if the British Monarchy used Agnatic Seniority?

Agnatic seniority, assuming we treat Elizabeth II as if she’s the founder of the monarchy (it’s actually Electress Sophia of Hanover, but as that was centuries ago that would be fiendish to figure out, so I’ll keep it simple for the sake of this example), would introduce much more drastic changes to the line of succession. Queen Elizabeth II had only one sibling, Princess Margaret, and she died 20 years before Elizabeth did. So it passes on to the next generation, the eldest son taking precedence, namely Charles, as in real life. But first in line to the throne would be not William but rather Charles’s younger sister, Princess Anne. She’d be followed by the infamous Prince Andrew and finally Prince Edward. Even after him William would not be next in line, for he’s not the eldest grandchild of QEII; that honor goes to Peter Phillips, followed by Zara Tindall, and only then would we see William and Harry in the line-up.

What if the British Monarchy used Ultimogeniture?

Ultimogeniture, especially absolute ultimogeniture, would introduce more drastic changes still. After Elizabeth II died she would have been succeeded not by her eldest son, Charles, but rather by her youngest son, Edward. First in line now would be Edward’s youngest child, James, Viscount Severn, followed by his elder sister Lady Louise Windsor.

Third in line would be Prince Andrew, followed by his youngest daughter Princess Eugenie, and her only son (so far; he was born just last year) August Brooksbank, then Princess Beatrice, and her only daughter (so far; she was born just last year too!) Sienna.


Ultimogeniture: a counter to Gerontocracy?

As a proponent of countering the creeping gerontocracy, and of the virtues of youthful vitality in leadership, I would vastly prefer ultimogeniture over primogeniture. Interestingly, it’s sometimes said by those who believe monarchy superior to democracy that monarchy works better because monarchs’ life terms are far longer time horizons than the next election in a couple years. Well, the younger the monarch is the longer their remaining life is, so I’d think they’d go gaga for ultimogeniture, but no, of course not: like almost all conservatives, they’re the foot soldiers of the gerontocracy.

Of course, ultimogeniture can engender gerontocracy too, albeit in less pronounced fashion than primogeniture. At 58, Edward is no spring chicken, but he could easily reign for decades in this scenario. Assuming he dies at, say, 90, his youngest child James would then be 46.

Let’s compare that to primogeniture. Charles is now 73; in fact he’s the oldest person to ever become British monarch (William IV was the previous record holder; 64 upon accession in 1830). Let’s say he dies at 90. His eldest son William would then be 57. If William also dies at 90 George would inherit the throne at the age of 59. Not a huge difference in this case, but you can see where this is going.

A Mandatory Retirement Age for Monarchs: how about 55?

One reform I would be a big fan of is imposing a retirement age for monarchs; it’s almost customary at this point for Dutch monarchs to abdicate in their old age, but the retired Queen Beatrix only stepped down at 75, which in my opinion is much too old to be leading a country. If you ask me we should go full Naboo and be done with it (all hail Queen Louise I!), but if we wish to not go full Naboo, if we are to be inclusive toward those in midlife while excluding only the truly elderly even 60 would be plenty high as a cap. For this objective a retirement age of 55 would be about right in my view. Hey, a retirement by 53 (and semi-retirement at 45!) was good enough for Bill Gates; why not monarchs too?

What if the British Monarchy used Ultimogeniture with a Retirement Age of 55

So let’s say we adopt absolute ultimogeniture coupled with a mandatory retirement age of 55. What would the succession to Elizabeth II have looked like? QEII herself would have retired when she reached 55, which was all the way back in 1981. She would have been succeeded by Prince Edward right then, who presumably would have been known as King Edward IX from his accession at the age of 17, and he would have reigned until he reached retirement age in 2019. At that time he would have been succeeded by his youngest child, James, aged 12. He’d now be 14, perhaps known as King James VIII. Yes, VIII; England had only two Jameses, but Scotland has had seven, and per Winston Churchill the higher of the two takes precedence.

If you ask me 17 and even 12 is old enough to reign without a regency, but if a minor must have a regent per the rule established in the Regency Act of 1937 the next person of age in the line of succession becomes regent (yes, in the actual act it’s 21, but that was the age of majority back then; if it were crafted nowadays it’d be 18). Under this ultimogeniture system, that’s currently none other than his older sister Louise, who turned 18 on November 8, 2021. Before that time Eugenie would have been Princess Regent.

Barring unforeseen circumstances Louise would continue as Princess Regent of the United Kingdom until James reaches the age of majority on December 17, 2025. James’s reign would be scheduled to expire when he reaches 55 on December 17, 2062.

King Edward IX, meanwhile, would have also acceded to the throne while underage. His regent would have been Prince Andrew, though his stint would have been brief, since Edward reached 18 on March 10, 1982, less than a year after his April 21, 1981 start date.

Let’s compare this system with imposing an age cap of 55 within today’s system. Elizabeth II still retires at age 55 in 1981, but is succeeded by Charles, as in real life, just 41 years (!) early. King Charles III then reigns from the age of 32 until he reaches the age of 55 in 2003. William then succeeds Charles, presumably as King William V, in 2003 at the age of 21, and he would still sit on the throne today, with his reign scheduled to expire on June 21, 2037. At that point George, presumably as King George VII, would take over at the age of 23, and reign until he reached 55 in 2068.


So it’s really the age cap that makes the difference, though ultimogeniture seems to help substantially. These sort of inverted inheritance systems coupled with age caps have much to recommend them, especially in a world rapidly grappling with old-age dependents taking the place of childhood dependents, and especially in a world where technological developments may well cause longevity escape velocity in the not-too-distant future, necessitating stronger mechanisms to funnel wealth and power out of the hands of the old and into the hands of the young. Science-fiction worldbuilders take note, and fantasy worldbuilders wonder “what if?”: monarchical succession can and should be far more interesting than modernity’s tame domesticated version.

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