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rootsandroutes 08-17-2014 10:52 PM

Number of Unique Ancestors of Queen Margrethe II of Denmark
Hi everyone,

I made a video called "How many ancestors do you have?" in which I use a model to estimate the number of individual people that a person is likely to have. Members here might be particularly interested to know that I used the first 20 generations of the genealogy of HM Queen Margrethe as the model, then extrapolated the growth rate in her unique ancestors back in time.

Even royalty have unknown ancestors, and I estimated that they grew at the same rate.

Anyway, I'd love it if Forum members would check it out! Thank you!

Ish 08-17-2014 11:25 PM

This was really interesting and informative.

I've read before the suggestion that mathematically at least everyone of European descent living today is descended from every European who lived 1,000 years ago and still has living descendants. This video seems like it's an expansion of that line of thinking, and presented in a very clear and concise way.

rootsandroutes 08-17-2014 11:27 PM

Thanks, Ish.

That's the idea exactly. There's so much great new work being done in this field with advances in autosomal DNA. I wouldn't be surprised if we were able to find out just how much thousand-year-old royals contributed to the gene pool in comparison to others.

Duc_et_Pair 08-18-2014 04:08 AM

It does not really work because there is quite a lot of overlap in royal marriages with shared bloodlines. The Dutch Prince Johan Willem Friso of Nassau, Prince of Orange (1687-1711) and his spouse, the Landgravine Marie Luise von Hessen-Kassel (1688-1765) hold the position of being the most recent common ancestors to all currently reigning European monarchs. The couple only got two children but nevertheless made it that all current reigning thrones are seated by one of their ancestors. There are lots of overlaps and shared bloodlines. For an example a British Princess who is an ancestor of Electress Sophia marrying with a Dutch Prince who is an ancestor of Electress Sophia as well. The formula works in theory but not in reality...


rootsandroutes 08-18-2014 11:09 AM

Total number of ancestors vs. MRCA (most recent common ancestor)
The Prince and Princess of Orange ca. 1711 being the most recent common ancestors of current reigning monarchs does not preclude those monarchs from having other ancestors. I take overlap into account, using real genealogical data.

Complete overlap just doesn't happen. I use Daniel de Rauglaudre's database for my model, which has the first 15 generations HM Margrethe II's unique ancestors (counting repeat ancestors only once) grow like this:

113 (Johan Willem Friso and Marie appear twice in this generation),
177 (twice again)
270 (twice again, being Margrethe's ancestors 6 times total)

Those 899 ancestors are a far cry from the 32,768 ancestors she would have in the 15th generation if they were all unique people! For comparison her cousin reigning in the UK has 1,317 in the same generation and the Duke of Edinburgh has 895. Why so different? The Queen Mother had many commoner English, Scottish, and Anglo-Irish ancestors, bringing her daughter's total up.

But even two people who are both *very royal* have ancestors whom we suspect do not overlap. The Duke of Edinburgh is descended from Maria Salomea Schweppenhäuser, Gräfin Hauke (1751-1833) while the Queen of Denmark is not. She was of Jewish ancestry and adds many ancestors to the former's ancestry that the latter does not have. Similarly, the Queen of Denmark is descended from Désirée Clary (1777-1860), the French wife of Karl XIV Bernadotte while the Duke of Edinburgh is not. Her ancestors were upper-class Marseillais, but certainly not royal.

It is this kind of growth that is modeled for Margrethe in my video, based on the real data.

Going back to those 15 generations, even royalty have unknown ancestors. I take these into account by assuming unknowns' ancestry grows at the same rate as known ancestors' ancestry. She has 899 ancestors in her 15th generation, including Johan IV of Nassau-Dillenburg (JWF's ancestor), who is Margrethe's ancestor through 197 lines in that generation (2,227 separate lines in total!). But she also has unknowns in that generation, and if I apply a coefficient of ancestor growth consistent with French minor nobility, for instance, it adds another 700 ancestors.

So then by the 20th generation, we wind up with an estimated ~6,000 ancestors for Margrethe, again, some of whom are her ancestors *thousands of times over* and who are the primary contributors to her being royal, but some of whom are unique commoners that she doesn't share with other monarchs. If it keeps growing at that same slow rate in the 20th through 150th generation, as her royal and noble ancestors fade into the Germanic and Celtic tribes of Old Europe, unknown Romans and others, her ancestors, too, start to go into the millions.

Ancestors of Margrethe II von Schleswig-Holstein-Sonderburg-Glücksburg
The Ethnic ancestry of Prince William

SLV 08-18-2014 12:12 PM

Well, this does explain the amount of common ancestors, I think.

rootsandroutes 08-18-2014 12:19 PM

Spreadsheet organization

I think I get the organization of your spreadsheet. I am used to looking at database printouts, instead, but I get it.

Focusing on the very dense network of relatedness, though, ignores where the royals are *not* related.

That's increasing very rapidly these days, now that the age of royal intermarriage is ended, and we have queens from Argentina and Panamanian princesses, however, royals *always* had some non-royal input into their bloodlines, whether official or not.

Meraude 07-11-2015 02:12 AM


Originally Posted by rootsandroutes (Post 1696000)
Focusing on the very dense network of relatedness, though, ignores where the royals are *not* related.

Even if there has been less intermarriages among non-royals than among royals, there has been a fair number of intermarriages between the members of aristocratic families. When it comes to commoners, even among them there were many intermarriages, especially if you go back 200 years and more, as people used to marry those living in the same village or town, as well as among the same/similar social class, and after a couple of generations there were a network of relatedness. Even the large cities in many countries had not a large population, for example Stockholm in Sweden had only 30.000 inhabitants in 1650 and in 1850 93.000. The city where I live was the third largest in Sweden in 1766 with a population of 10.000, and the fourth largest in 1850 with 14.000 inhabitants, so there had to be a number of intermarriages. It's only the last 100-150 years that people are more likely to marry someone they have no relatedness to.

aubri 08-23-2015 05:41 PM

I am related to Herbastus King of Denmark Herfast De Crepon, not sure if the line leads to Margrethe or not.

Muhler 08-23-2015 06:15 PM

:previous: Who is he?

Did a quick Google. Harald Bluetooth. Yes, QMII can trace her linage back to his father. Not an entirely straight line, but nevertheless a direct link.

aubri 08-23-2015 06:51 PM

Harold Blue Tooth Gormsson is my 34th great grandfather. :) Good stuff, really enjoying the wealth of knowledge from you guys. Thanks Muhler. :) This stuff can be soooo confusing!

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