below is a chart summarizing the findings from various consanguinity studies for england (and a couple for scotland). i’ve adapted catherine linley day’s chart which appears in her thesis [opens pdf] on pg. 245 (basically, i’ve added her findings, fleshed out darwin’s findings, and added a couple of others — i also divided the findings between north and south). most of these studies have drawbacks and lynley day goes through them all in detail on pages 245-250. click on image for LARGER view:
as you can see, and as i mentioned yesterday, the overall pattern seems to be that people in southern great britain have largely avoided cousin marriage since the 1500s (possibly as far back as the 1300s), while the people further north, not so much. if anything, cousin marriage increased in the succeeding centuries, particularly in the nineteenth (a general pattern for much of europe).
the sorts of cousin marriage rates we see for the english from the medieval period to the modern — ranging from 0.00 to 5.30 — are just not even in the same
ballpark cricket pitch as other parts of the world like the arab peninsula or even southern europe. and they haven’t been. for centuries. the english, especially members of the southern subspecies, have apparently avoided cousin marriage like the plague.
there are gaps, i know. big gaps. more numbers would be nice, of course. further research is required. (~_^)
let me go through the list.
the first entry for fourteenth century ely. i posted about that here. fifty percent (50%) of all marriages in ely, cambridgeshire, in the 1300s were to people living outside of ely. hard to know if this means people were avoiding cousin marriage or not — people from ely could’ve been marrying their cousins living in other villages — but it’s likely, i think, that this means they were avoiding marrying close family members. at this point in time, the roman catholic church had banned cousin marriage up to and including third cousins, and as lynley day points out with regard to the second entry on the list (1500s england), for whatever reasons, medieval english people seemed to take these restrictions seriously [pg. 246]:
“Marriage dispensations from the reign of Henry VIII were used to estimate consanguinity (Smith et al. 1993). The results produced from these documents were surprisingly low (Table 6-4), with a total absence of 1st cousin marriages and a very low level of 2nd cousin marriages, even compared to modern studies. One possible explanation, as noted by Smith and his colleagues, is that the marriage dispensations may not reflect actual practice, although anecdotal evidence suggests that there was a real aversion to close consanguineous marriage in the mediaeval period (Smith et al. 1993). Another explanation proffered is that marriage dispensations were almost exclusively the preserve of the rich, and that the poor and labourers did not avail themselves of the system (Smith et al. 1993).”
the third item on the list is lynley day’s study which i posted about yesterday. the next is bramwell’s study for shropshire. bramwell used george darwin’s techniques to calculate cousin marriage rates in that county by looking at surnames. his results are not far off lynley day’s and so, i’d guess, are probably fairly accurate. the same can be said for darwin’s results (which i posted about here).
pearson’s hospital study involved checking for consanguinity between the parents of sick children. while consanguineous couples might have more sickly children on average compared to the rest of the population, pearson’s finding of 1.3% first cousin marriages for londoners of the time also seems to fit well with the other findings. he attempted to double-check his results by surveying the readers of the british medical journal (bmj), but he may have gotten a skewed response (only persons married to cousins responding) and/or many of the readers at the time may have been from the upper classes. one or both of those may account for the high (for england) 4.69% first-cousin marriage rate that he found.
the next study, bell’s study of hospital patients across england, had the same methodology as pearson’s, but found a slightly lower consanguinity rate. but the late nineteenth century/early twentieth century (when the study was conducted) is just the point when consanguinity rates started to drop across europe after peaking between 1875-1915, so that may account for the lower rates.
smith’s study of the records of the society of genealogy members probably has a slight bias towards middle-/upper-class folks who, as g. darwin showed, tend to have slightly higher consanguinity rates in england (and elsewhere, too, i think). finally, the study of consanguinity rates in twentieth century reading by coleman can be found here.
previously: consanguinity in england – north vs. south and but what about the english? and cousin marriage rates amongst nineteenth century english and english jews and exogamous marriage in medieval england and invention of the modern world
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