How many people share a great-to-the power-of-eight grandparent?

Question

I just discovered that King George II was one of my 1,024 great great great great great great great great grandparents (great-to-the-power-of-eight). On average, how many other people would also share this relationship to him?

Answer 1

It is - statistically - going to be quite high. The point is that most people aren't going to be able to show HOW they are connected to G II, so you're lucky that you can. Only in a handful of cases have I been able to trace a line back to the 1720s and 1730s (but George II does not appear anywhere in my family tree!)

You're also unlikely to actually have 1,024 8xgt grandparents alive in the first half of the 18th century - some of them will appear on more than one side of your family.

To give you an idea of the numbers involved, very roughly, we'll say that there are 50 million people in Britain today who had ancestors alive in the time of Geo. II - that's children, parents and grandparents; so lets say there are 25 million parents today. For just 10,000 people - 0.04% of the current number of parents alive today - not to a) be related to each other and b) to have had ancestors since the George II's time who equally weren't related to each other, there would have to have been a population of 10,000 times 1,024 (= 10,240,000).

The population of England was something like 5.5million - again, covering 3 generations at least - and from which today's current indigenous UK population descends, as well as no doubt several million people in Canada, Australia, NZ, the US, etc...

So while answering your question with anything like precision might be impossible, you can start to see that there must have been a lot of inter-marrying and that your claim of descent from Geo II is statistically insignificant, even allowing for aristocratic in-breeding. But, as I say, the real point is that you've been able to do it at all - most of us aren't going to be able to do that.

Answer 2

As the royals are more inbred than most, not as many that would share mine or one of your other great to the power of eight grandparents.   In fact I am willing to bet we share one of those.

Answer 3

Impossible to answer, particularly since that particular family kept marrying cousins. Some people might have that (or a similar) relationship to him several times over!

Answer 4

Much less than the average person--Prince Charles has only 11,306 ancestors in the last 17 previous generations that have come before him as opposed to the 131,070 that he would otherwise have had if cousins had not married cousins in many different generations. The less ancestors one has the less descendants one's ancestors have. But then, such are the perils of "pedigree collapse".

Answer 5

Firstly you 256 have great (x8) grandparents and not 1024!

Secondly, King George II has a widely documented lineage, and only 4 of his children had issue: the Prince of Wales (George III's father), Princess Anne of Orange, Princess Mary Landgravine of Hesse and Queen Louise of Norway and Denmark. I am surprised you had just found out you were descended from him, since most of his living descendents are still royals or nobles and are in the line of succession to the throne.

George II is also the great (x8) grandparent of Prince William, so anyone in the same line as he.