This article is from the archive of our partner .

The natural question, upon the occasion of the birth of the royal baby is: How long until this tiny infant becomes King? And the answer is: November 6, 2060, when he is 47 years old. How do we know this? Because of math and guessing, naturally.

The way the British monarchy works, in rough terms, is that a new monarch is crowned upon the death of the existing one. At birth, there will be three people in between Little Baby Whomever and the throne, all of whom will need to die (or abdicate, which seems unlikely, Belgian example notwithstanding) before Whomever's reign can begin: First, Queen Elizabeth, then Prince Charles (Whomever's grandfather), and then Prince William (Whomever's dad).

So how can know when all of that will happen? The short answer is: we can't. But the long answer is: we can guess by looking at trends.

One trend that isn't helpful is the history of ascension in the English/British monarchy. Looking at every king or queen back to Æthelstan, born in 895, gives us the following picture of the monarchy. Each monarch has a vertical bar. The yellow section is his or her life prior to assuming the throne; the purple, the part after ascension until death. (We've included Elizabeth II at far right, extending the purple to 2013.)

This is imprecise, if nonetheless informative. As you can see, monarchs have been assuming the throne at later ages recently, as monarchs themselves tend to live longer. By way of illustrating that point more clearly, The average age at which a monarch ascended the throne is about 30 for all monarchs, with the age of death being around 50. For only those monarchs who assumed the throne after the Commonwealth in the mid 17th century, the average age of ascension has been 41 and the age of death 66.

But that's imprecise, and subject to weird aberrations — like a monarch who assumed the throne at the age of 26 and still sits upon it. Happily, we now live in a modern era during which we can make better predictions about how long people will live. So that's what we've done.

Using the exceptional datasets in WolframAlpha, we figured out the average life expectancies of people born at the time of each of those in line for the throne, and, therefore, the point at which we might assume the next person in line will be called to duty.

That data gives us this table.

  Date of birth Age at ascension Life expectancy Probable date of death
Elizabeth II Apr. 21, 1926 26 92.88 years Mar. 8, 2019
Prince Charles Nov. 14, 1948 70 82.15 years Jan. 7, 2031
Prince William June 21, 1982 47 78.38 years Nov. 6, 2060


And with William's death at 78 in November 2060, 31 years after assuming the throne, we get King or Queen Whomever, at long last. There are way too many variables to list in full here — including abdications, exceptional longevity, great tragedy, and the exceptional medical benefits of being monarch — but the pure actuarial data is what it is.

If you're a particularly morbid type, we can also predict when King Whomever's kids will assume the throne. That differs depending on gender. Life expectancy for a king born today, indicates that he'll live to October 3, 2090. (For a queen, it would have been January 31, 2095.) And if the data is correct, King Whomever will have been monarch from 2060 to 2090 — 30 years precisely, exactly in line with historical precedent.

Photo: Britons await news of their eventual monarch. (AP)

This article is from the archive of our partner The Wire.