Putting together the pieces

1) rates of inter-country migration

The results of my poll on this are really rather startling. 87 of you answered all three questions. You report that of your 174 parents, 24 (14%) were born in different countries to you; and of your 348 grandparents, 73 (21%) were born in different countries to you. (So you guys are more likely to have been born in a different country to your parents than they are to have been born in a different country to theirs.)

But even making allowances for that, the rate of inter-country migration used by Rohde in his paper – 0.1%, one in a thousand – seems far too low. One in seven of your parents was born in a different country to you. One in twelve of your grandparents was born in a different country to their child who became your parent. The “true rate” migration worldwide today may well be much higher than I had realised.

It could be argued that moving from country to country has become easier and more common in the last few decades, and the fact that one in seven of your parents, but only one in twelve of their parents, was born in a different country to their child might be an indicator of this. Myself I’m more inclined to put this down to the selection effect that those people who respond to polls in my livejournal are probably more likely to have an interest in travel, as I do, and to have had parents who, like mine, were also interested in travel.

It’s only impressionistic, but it seems to me that migration from country to country has been pretty frequent for a very long time. As I look at my history shelf, the nearest book is F.E. Peters’ study of Jerusalem, which chronicles the waves of settlement over that city in the last 3000 years starting when David conquered it from the Jebusites. Next along is my abridged versioon of Gibbon’s Decline and Fall of the Roman Empire. On the same sheld I have Peter Balakian’s account of the Armenian genocide and diaspora, Keay’s History of India and a collection of essays on the life of the much-travelled twelfth-century queen Eleanor of Aquitaine (whose son Richard I, if you remember, was married to a Spanish princess shortly after conquering Cyprus). Probably it’s even easier now than it was, and probably more people can travel now than did a hundred years ago; but I reckon most of us in, as Nick Barnes put it, the area north of the equator and west of the Gobi (and going west right the way round to California) have common ancestors in the last 800 years.

2) I wortoe before that [Rohde’s] model assumes that women have an equal probability of bearing children every year between the ages of 16 and 40, thus giving an average age difference between mothers and their children of 28. I reckon this flattens out the natural bump (!) at the lower end of that age range, and my suspicion (without any proof) for most of human history is that most children were born to women aged between 14 and 30. That too will decrease the time to our most recent common ancestor, as the time between generations will be shorter.

speculated that Most children may have been born to women between 14 and 30 but the ones born to older mothers may be more likely to have survived (and their mothers to have died as a result or shortly after). A large number of children born to younger mothers succumbed to poor infant care (nursemaids dropping babies off battlements, bizarre infant-rearing theories not contradicted by inexperienced parents, malnutrition etc)..

Interesting point. It’s not a scientific sample, but the easiest data to get for, say 1250 AD, are the statistics for reigning monarchs and their queens of the day.

Queen of England: Eleanor of Provence (married to Henry III). She was born in 1223, married in 1236. Her children who survived to adulthood were:
Edward I ‘Longshanks’, King of England b. 17 Jun 1239 (mother 16)
Margaret of England b. 29 Sep 1240 (mother 17)
Beatrice of England b. 25 Jun 1242 (mother 19)
Edmund ‘Crouchback’ Plantagenet, Earl of Leicester+ b. 16 Jan 1245 (mother 22)

Queen of France: Eleanor’s elder sister Marguerite (married to St Louis IX), born around 1221, and married in 1234. Her children who survived to adulthood were:
Isabelle (March 2, 1241–January 28, 1271) (mother 20)
Philippe III (May 1, 1245–October 5, 1285) (mother 24)
Jean Tristan (1250–August 3, 1270) (mother 29)
Pierre (1251–1284) (mother 30)
Blanche (1253–1323) (mother 32)
Marguerite (1254–1271) (mother 33)
Robert, Count of Clermont (1256–February 7, 1317) (mother 35)
Agnes of France (c. 1260–December 19, 1327) (mother about 39)

Queen of Norway: Margret, married to Haakon IV in 1225; I don’t have a date of birth for her, but her father was born only in 1189 so if he was 36 when she was married she must have been born between 1205 and 1210. Their children who survived to adulthood were born in 1232, 1234 and 1238 (another born in 1226 died in infancy).

Margaret, Countess in her own right of Flanders and Hainault, had had children when she was 16, 19 and 24.

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1 Response to Putting together the pieces

  1. smhwpf says:

    I’ve been thinking for a long time that Armenia-Azerbaijan is both one of the few clear-cut honest-to-god inter-state arms races around, and a major conflict danger. The rate Azerbaijan have been increasing their military spending is scary; and the 2011 increase, I read in one place that they’re actually increasing the budget by 80% – that seems a pretty clear declaration that they’re going to use that if it doesn’t cause Armenia to shift at the negotiating table.

    I take it this isn’t a region you work on nowadays? We have someone at SIPRI who’s big on the Caucasus and generally interested in collaboration on the subject.

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