The evolution of Cavalli-Sforza. Part I

Germ warfare was a priority for both Allied and Axis scientists. Was one of them a young L.L. Cavalli-Sforza?

With an academic life spanning almost half a century, L.L. Cavalli-Sforza has become perhaps the foremost authority on human population genetics.

He first entered this field in the early 1940s. As a medical student at the University of Pavia, he encountered Emilio Veratti, who lectured on Italian genetics, and Adriano Buzzati-Traverso, who specialized in fruit fly genetics. He went on to study the genetics of bacteria, specifically how to select strains that can better resist radiation and nitrogen mustard (mustard gas):

Starting in 1941, bacteria had become my major interest and in 1948 I gave a paper at the International Congress of Genetics in Stockholm on cross resistance to radiation and nitrogen mustard in E. coli based on work done earlier in Milan with Niccolo Visconti (Cavalli-Sforza 1992).

This account, written forty years after the facts, is consistent with a description he gave in 1950:

Nitrogen mustard resistance was found to be gradual or abrupt in increase in different experiments, only a moderate degree of resistance being acquired, which made a detailed analysis difficult. In E. coli K-12 nitrogen mustard resistance is not accompanied by higher resistance to radiations, as in the case of E. coli B. (Cavalli & Maccacaro 1950)

In the same article, he also described experiments to make E. coli more resistant to chloromycetin, an antibiotic. It is not clear where, when, or for whom this work was done, although some of this research could have been postwar (or early war, i.e., before the U.S. entry in Dec. 1941). The co-author, G.A. Maccacaro, had been supported by a grant from the Rockefeller Foundation, and the K-12 strain had been supplied by an American researcher.

In an earlier article, however, Cavalli-Sforza reported findings from another research project. These findings were the mean death times (i.e., time to death) of mice in response to progressively higher doses of anthrax and pneumococci (Cavalli & Magni 1947). This research was novel in that it measured time to death, as opposed to the percentage killed.

To learn more about this period of Cavalli-Sforza’s life, we can turn to his recent autobiography. Among other things, his research work took him to Germany:

I went to see him [Emilio Veratti] to ask him for advice about certain bacteriological research that I had conducted with Giovanni Magni, my college and faculty classmate. It had to do with a study on bacterial virulence using a mathematical method. Veratti told me that to his knowledge the only person who could help us was a German professor, Richard Prigge. We later discovered he was right.

[…] With Magni, in Como, we studied anthrax, which is still talked about today because it is one of the most fearsome bacteriological weapons

[…] it was not so difficult to measure bacterial virulence [in mice] and we continued our research because we really wished to study this mechanism with a view to creating possible vaccines.

At this point, the advice of Veratti, who had suggested that we try to obtain a scholarship to study at Frankfurt am Main with Prof. Prigge, the only European scientist who could understand the worth of our experiments, proved to be useful. We had the luck of getting a scholarship to spend the summer [of 1942] in Germany. (Cavalli-Sforza & Cavalli-Sforza 2008, pp. 31-34)

The autobiography mentions another stay in Germany, this time with the renowned geneticist Timofeeff-Ressovsky:

Buzzati asked us, Magni and me, to join him in Berlin, in August 1942, at the Berlin-Buch Kaiser-Wilhelm Institute of Genetics (now the Max-Planck Institute). It was a bit before our research stay in Frankfurt with Prigge.

At the time, the Institute was run by the famous Russian geneticist Nikolai Wladimirovich Timofeeff-Ressovsky, a man of an extraordinary personality, intelligent, likeable, and enthusiastic; in sum, very Russian.

[…] After my meeting with N.W. Timofeef, I decided that I would devote my career to genetics research. (Cavalli-Sforza & Cavalli-Sforza 2008, pp. 39)

One gets the impression that the meeting with Timoffeef in Berlin happened during a short stay, perhaps a single visit. Yet when Cavalli-Sforza dedicated his genetics textbook to Timoffeef in 1947, he called him “a friend and teacher, with the wishes that he will be able to continue his work” (Cavalli & Buzzati-Traverso 1947). These words suggest a longer working relationship.

Cavalli-Sforza’s autobiography provides the best account of his wartime research, but certain details contradict those in his earlier accounts. For one thing, the earlier ones (with one exception) have him studying E. coli, and not anthrax, although this contradiction may be more apparent than real. He could have been working with E. coli as a prelude to riskier work with anthrax. Alternatively, the E. coli work may have been postwar.

But the contradiction is more fundamental when it comes to his research aims. The earlier accounts have him seeking to create more resistant strains of bacteria, and not better vaccines. These two aims are contradictory because vaccines are normally made from weaker, not stronger strains. Perhaps he also wished to study drug resistance—a legitimate subject of medical enquiry. But why was he also interested in bacterial resistance to radiation and mustard gas?

This sounds more like germ warfare research. More precisely, he seemed to be working on ways to combine anthrax with chemical and radioactive agents, presumably as part of a single warhead.

We’ll probably never know the whole story. Perhaps even Cavalli-Sforza didn’t know. And does it matter? Neither side used germ warfare in WWII, out of fear that the other side would retaliate in kind. (Yes, our side had its own germ warfare program).

Still, it does matter. It certainly did to Cavalli-Sforza. He apparently dreaded having his wartime record brought up, and this dread would guide his behavior later in life ...

Note

During the war years and the immediate postwar era, Cavalli-Sforza published under the name of Cavalli. To date, I have been unable to locate his four wartime articles or even their titles.

References

Bonezzi, G, L.L. Cavalli, and G. Magni. (1943). Zentralbl Bakteriol, I Orig, 150, 17–25.

Cavalli, L. L., and G. Magni. (1947). Methods of analysing the virulence of bacteria and viruses for genetical purposes, Heredity, 1, 127–132; doi:10.1038/hdy.1947.8
http://www.nature.com/hdy/journal/v1/n1/abs/hdy19478a.html

Cavalli, L. L., and G. Magni. (1943). Zentralbl Bakteriol, I Orig, 150, 25–32.

Cavalli, L.L., and G. Magni. (1943). Zentralbl Bakteriol, I Orig, 150, 353–371.

Cavalli, L.L., and G. Magni. (1942). Boll d Soc Med Chir Pavia, 20, 609–624.

Cavalli, L.L. and G.A. Maccacaro (1950). Chloromycetin resistance in E. coli, a case of quantitative inheritance in bacteria, Nature, 4232, 991-992.

Cavalli, L.L. and A. Buzzati-Traverso (1947). Teoria dell'urto ed unità biologiche elementari, Milan, Longanesi.

Cavalli-Sforza (1992). Forty years ago in genetics: The unorthodox mating behavior of bacteria, in J.F. Crow and W.F. Dove (eds). Anecdotal, Historical and Critical Commentaries on Genetics, Genetics Society of America.http://profiles.nlm.nih.gov/BB/B/C/C/Z/_/bbbccz.ocr

Cavalli-Sforza, L.L. and F. Cavalli-Sforza (2008). La génétique des populations : histoire d'une découverte, Odile Jacob.

A late convert

Cavalli-Sforza with Kistler Prize (2002). The paths of Glory lead …

Human Biology has interviewed Luigi Luca Cavalli-Sforza, probably the best-known human geneticist (Manni, 2010). His worry? The growing rift between anthropology and biology:

Unfortunately, at least in the United States, anthropology is in decline: The cultural moiety is separating from the rest and loves to declare that it is not science—what is it, instead? The rest of the U.S. anthropology departments (variable according to places, but mostly a mixture of physical anthropology, primatology, archaeology, linguistics) fortunately seem to resist this trend, but anthropology seems to be losing ground. There is a need for a new anthropology capable of keeping unity, and to develop human science curricula that may promote an original, fresh outlook.

Why this retreat from biology? Ask almost any anthropologist. You’ll be told that there is much more genetic variation within human populations than between them. With culture, we see the reverse: the differences are primarily between populations. So how can genetic differences explain cultural differences? Such explanations are inevitably wrong and, needless to say, dangerous.

And you’ll be told that this view is endorsed by all credible geneticists, including Cavalli-Sforza. Just read the same interview:

Don’t you feel that results pointing to intracontinental genetic differences can reinforce racist theories, as some pharmacogenomic studies recently did?

LLCS: The between-population genetic variation observed with 650,000 SNPs on the 52 populations of the HGDP is 11% (Li et al. 2008) with a very small standard error. It becomes 16% for the X chromosome, as is expected if nearly all the genetic variation is due to drift—that is, the role of natural selection is very limited. The ca. 30-year-old estimate by Lewontin (1972) of this quantity (15%) was based on other markers and populations and was a reason to encourage banning the use of the word race in humans. In any case the new value is even more supportive of dropping the word race. What we really need to ban is racism, and this is not a socially easy-to-do program. Charles Darwin, already, was skeptical about the usefulness of the race concept in humans, having noted that human variation is geographically almost continuous for most traits.

Man has been studied more carefully than any other animal, and yet there is the greatest possible diversity amongst capable judges whether he should be classed as a single species or race, or as two (Virey), as three (Jacquinot), as four (Kant), five (Blumenbach), six (Buffon), seven (Hunter), eight (Agassiz), eleven (Pickering), fifteen (Bory St. Vincent), sixteen (Desmoulins), twenty-two (Morton), sixty (Crawfurd), or as sixty-three, according to Burke. This diversity of judgment does not prove that the races ought not to be ranked as species, but it shows that they graduate into each other, and that it is hardly possible to discover clear distinctive characters between them. (Darwin 1871: 226)

Well, no. Darwin was not “skeptical about the usefulness of the race concept in humans” In the above quote, he was denying that humans had diverged into different species. But he did not deny the reality of human races, as he stated a few pages previously:

There is, however, no doubt that the various races, when carefully compared and measured, differ much from each other,—as in the texture of the hair, the relative proportions of all parts of the body, the capacity of the lungs, the form and capacity of the skull, and even in the convolutions of the brain. But it would be an endless task to specify the numerous points of difference.

[…] If a naturalist, who had never before seen a Negro, Hottentot, Australian, or Mongolian, were to compare them, he would at once perceive that they differed in a multitude of characters, some of slight and some of considerable importance. On enquiry he would find that they were adapted to live under widely different climates, and that they differed somewhat in bodily constitution and mental disposition. If he were then told that hundreds of similar specimens could be brought from the same countries, he would assuredly declare that they were as good species as many to which he had been in the habit of affixing specific names.

But why bother quoting Darwin? It’s more fun to quote Cavalli-Sforza!

The differences that exist between the major racial groups are such that races could be called subspecies if we adopted for man a criterion suggested by Mayr (1963) for systematic zoology. Mayr’s criterion is that two or more groups become subspecies when 75 percent or more of all the individuals constituting the groups can be unequivocally classified as belonging to a particular group. As a matter of fact, when human races are defined fairly broadly, we could achieve a much lower error of classification than 25 percent, implying, according to Mayr, the existence of human subspecies. (Cavalli-Sforza & Bodmer, 1977)

Well, that was Cavalli-Sforza back in 1977. Perhaps he was still unaware of Richard Lewontin’s finding that genes vary much more within human populations than between them. Was not this “a reason to encourage banning the use of the word race in humans”?

Except that Lewontin had published that reason in 1972. Five years later, Cavalli-Sforza was apparently still unimpressed. And he continued to use the race concept much later, as in this journal article from the late 1980s:

The first split in the phylo-genetic tree separates Africans from non-Africans, and the second separates two major clusters, one corresponding to Caucasoids, East Asians, Arctic populations, and American natives, and the other to Southeast Asians, (mainland and insular), Pacific islanders, and New Guineans and Australians (Cavalli-Sforza et al., 1988).

Cavalli-Sforza did not convert to race denialism until the mid-1990s, with his opus The History and Geography of Human Genes.

What motivated his conversion? Had Lewontin’s 1972 paper been further bolstered by new data and arguments? Not really. In fact, the 1980s and 1990s saw growing evidence that the same genetic overlap that Lewontin found between human populations also occurs between many species that are nonetheless distinct in anatomy, physiology, and behavior (see previous post).

As one anthropologist told me: “I don't think our perception of the general patterns of genetic variation changed much from '76 to '94, but the intellectual climate that geneticists operate in sure did.”

References

Cavalli-Sforza, L.L., P. Menozzi, and A. Piazza. (1994). The History and Geography of Human Genes. Princeton: Princeton University Press.

Cavalli-Sforza, L.L., A. Piazza, P. Menozzi, and J. Mountain. (1988). Reconstruction of human evolution: Bringing together genetic, archaeological, and linguistic data. Proc. Natl. Acad. Sci. USA, 85, 6002-6006.

Cavalli-Sforza, L.L. and W.F. Bodmer. (1977). The Genetics of Human Populations, San Francisco: W.H. Freeman and Co.

Darwin, C. R. (1871). The Descent of Man, and Selection in Relation to Sex. London: John Murray.

Lewontin, R.C. (1972). The apportionment of human diversity. Evolutionary Biology, 6,
381-398.

Manni, F. (2010). Interview with Luigi Luca Cavalli-Sforza: Past research and directions for future investigations in human population genetics, Human Biology, 82, 245–266.

On infidelity

Demon of lust. Chartres Cathedral. To create larger and more complex societies, humans had to restrain impulses that were hitherto considered normal.

Michelle Langley has written an interesting critique of modern sexual behavior, especially with regard to women, In Women’s Infidelity, she argues that:

…. young females are conditioned to believe that they are naturally monogamous and they carry this belief with them throughout their lifetimes. So when women experience feelings that deviate from this belief, particularly after they are married, those feelings can cause enormous internal conflict. Many women resolve the dilemma by dissolving their marriages.

Some women find it easier to think they married the wrong guy than to see themselves as some sort of shameful freak of nature. Their erroneous belief in a monogamous predisposition prevents them from becoming aware of their natural sexual tendencies in the first place. This unawareness can cause a chain reaction that
ultimately destroys their marriages. (Langley, 2005, pp. 19-20)

Evolutionary psychologists have long assumed that women are hardwired for monogamy. Men presumably learn to be monogamous. Today, both assumptions are in need of rethinking. As we strip away layer after layer of cultural restraint, female sexuality is deviating more and more from its supposedly innate pattern.

The truth is that culture has limited both male and female sexual behavior, specifically by restraining impulses that were hitherto considered normal. This is the price for living in larger and more complex societies. Such social environments work best when individuals can readily cooperate with others, particularly those of the same sex. No one trusts a sexual rival, and nothing destabilizes a society like large numbers of single men. To avoid this scenario, our ancestors had to limit male polygamy and female hypergamy.

How did they do it? In part, circumstances had already done it for them. In part, they consciously did it to themselves. This new niche was most successfully exploited by northern Eurasians who were already highly monogamous, since non-tropical environments made women and children more dependent on men, particularly in winter (Frost, 2008). Our ancestors then imposed cultural restraints to further limit male polygamy and female hypergamy—by shaming, ostracizing, and killing “deviant” individuals.

And now, as the restraints come off, we are no longer—surprise! surprise!—these faithful beings we thought we were.

The time has come to drop the idea that men and women are naturally good. This is a naïve kind of sociobiology that sees culture as an enemy—an unnatural force that prevents us from being truly human (and having fun!). Actually, culture is the main force that has made us human. It has helped us meet the requirements of new environments that are human-specific and that humans would have never colonized without its help. It has been part of our adaptive landscape, no less so than climate or food supply. And, as such, it has favored humans with the right predispositions and personality traits.

But this co-evolution is never complete. Our biological self always lags behind our cultural self. To the extent that we strip away the latter, we become less adapted to our environment. In plain language, we lose part of what we are.

References

Frost, P. (2008). Sexual selection and human geographic variation, Special Issue: Proceedings of the 2nd Annual Meeting of the NorthEastern Evolutionary Psychology Society. Journal of Social, Evolutionary, and Cultural Psychology, 2(4), pp. 169-191.
http://www.jsecjournal.com/articles/volume2/issue4/NEEPSfrost.pdf

Langley, M. (2005). Women’s Infidelity. Living in Limbo. What women really mean when they say, “I’m not happy.” St. Louis (Mo): McCarlan Pub.

More on European hunter-gatherers

Medieval (?) ice cellar for meat storage (Sweden). Link: runlama
In northern climates, the yearly cycle of changing temperatures encouraged humans to think ahead to the next season.

My last post mentioned the debate over the provenance of present-day Europeans. Do they descend from the hunter-gatherers of Upper Paleolithic and Mesolithic Europe? Or were those people a dead end? Were they replaced by Middle Eastern farmers when agriculture spread into Europe 9,000 to 3,000 years ago?

This debate will eventually be settled when we can genetically compare late European hunter-gatherers with early European farmers. And ‘eventually’ is not far off. Much data will come on-stream over the next three years, probably enough to end the debate. The evidence will probably show that European hunter-gatherers did adopt farming, but not all of them to the same extent. Some did so before others and thus expanded at the latter’s expense. So my hunch is that European farming spread both culturally and demographically. The early farmers were not a random sample of the late hunter-gatherers.

But why is there so much resistance to the idea that European hunter-gatherers became farmers? One reason is that hunter-gatherers do not easily take to farming. This is a point that the anthropologist Marshall Sahlins made. Becoming a farmer is not just a matter of learning new techniques. It’s also a matter of acquiring a different outlook that is geared to future consumption. “Short-term pain for long-term gain.” Food has to be planted in the spring, harvested in the fall, and stored for winter.

Such a trade-off is rare in hunter-gatherer societies. There’s no point in tending a plot of land because you’re constantly on the move. There’s also no point in holding on to stuff because it has to be carried around.

As Sahlins (2005) puts it:

The hunter, one is tempted to say, is "uneconomic man". At least as concerns non subsistence goods, he is the reverse of that standard caricature immortalised in any General Principles of Economics, page one. His wants are scarce and his means (in relation) plentiful. Consequently he is "comparatively free of material pressures", has "no sense of possession", shows "an undeveloped sense of property", is "completely indifferent to any material pressures", manifests a "lack of interest" in developing his technological equipment.

Sahlins quotes from a monograph on the Yahgan Indians:

They do not know how to take care of their belongings. No one dreams of putting them in order, folding them, drying or cleaning them, hanging them up, or putting them in a neat pile. If they are looking for some particular thing, they rummage carelessly through the hodgepodge of trifles in the little baskets. Larger objects that are piled up in a heap in the hut are dragged hither and thither with no regard for the damage that might be done them.

The European observer has the impression that these (Yahgan) Indians place no value whatever on their utensils and that they have completely forgotten the effort it took to make them. Actually, no one clings to his few goods and chattels which, as it is, are often and easily lost, but just as easily replaced [...] The Indian does not even exercise care when he could conveniently do so. A European is likely to shake his head at the boundless indifference of these people who drag brand-new objects, precious clothing, fresh provisions and valuable items through thick mud, or abandon them to their swift destruction by children and dogs [...] Expensive things that are given them are treasured for a few hours, out of curiosity; after that they thoughtlessly let everything deteriorate in the mud and wet. The less they own, the more comfortable they can travel, and what is ruined they occasionally replace. Hence, they are completely indifferent to any material possessions.

For all these reasons, farming has spread more through the expansion of an existing population of farmers than through the conversion of hunter-gatherers.

Sahlins based his conclusions on those hunter-gatherer groups that exist today, generally tropical or semi-tropical groups like the !Kung and the Australian Aborigines. We know much less about the hunter-gatherers who used to roam across Europe. But we do know that they were more future-oriented and possession-oriented.

First, the changing seasons imposed a yearly cycle of resource availability. Natural selection thus favored humans who could plan their behavior with an eye to the next season. For example, it favored the construction of “ice cellars”—deep storage pits dug down to the permafrost as a way to store meat for future use (Hoffecker 2002, p. 161).

Second, the colder climate limited the number of game animals per square kilometer, thus forcing hunters to cover a larger land surface. This in turn favored a capacity to generate mental models of animal movement over space and time. It also favored a capacity (or rather a willingness) to manage traps and snares by periodically checking them.

As Hoffecker (2002, p. 135) notes about early modern humans, tools and weapons were more complex at arctic latitudes than at tropical latitudes. “Technological complexity in colder environments seems to reflect the need for greater foraging efficiency in settings where many resources are available only for limited periods of time.”

Non-tropical humans coped with seasonal variation in resources by planning ahead. They were thus “pre-adapted” for later developments in cultural evolution, including the advent of agriculture.

References

Hoffecker, J.F. (2002). Desolate Landscapes. Ice-Age Settlement in Eastern Europe. New Brunswick: Rutgers University Press.

Martin, G. (1961). The Yamana, 5 vols. New Haven, Conn.: Human Relations Area Files. (German edition 1931).

Sahlins, M. (2005).

The Original Affluent Society [Online] in M. Sahlins, Stone Age Economics

How long have Europeans been European?

How long have Europeans been in Europe? Clearly, their ancestors were not Neanderthals, except for an admixture of 1 to 4%. What about the modern humans who came about 35,000 years ago as hunter-gatherers? Or did they too die out? Were they replaced by Middle-Eastern farmers some 9,000 to 3,000 years ago?

This is an ongoing debate and a single study will not decide things one way or the other. In recent years, the evidence has been shifting towards the replacement model. In northern Europe, there seems to have been a genetic divide between late hunter-gatherers and early farmers (although the divide is just as great between the latter and present-day Europeans). In particular, European hunter-gatherers possessed genetic lineages (haplogroup U) that are rare among present-day Europeans.

Now, the pendulum is swinging back. After studying 92 Danish human remains that range in time from the Mesolithic to the Middle Ages, Melchior et al. (2010) have found evidence of genetic continuity from late hunter-gatherers to early farmers.

The extent to which early European farmers were immigrants or descendants of resident hunter-gatherers (replacement vs. cultural diffusion) has been widely debated, and new genetic elements have recently been added. A high frequency of Hg U lineages, especially U5, has been inferred for pre-Neolithic Europeans based on modern mtDNA data, with Hg U5 being fairly specific to Europe.

[…] The present findings indicate that predominantly haplogroup U lineages persist among Neolithic/Bronze Age population samples in Southern Scandinavia and it may point to regional variation in the penetrance rate of these lineages across cultural shifts in different areas of North Europe. Given our small sample sizes from these crucial time periods further studies are certainly required. However, the frequency of Hg U4 and U5 declines significantly among our more recent Iron Age and Viking Age Danish population samples to the level observed among the extant Danish population. Our study therefore would point to the Early Iron Age and not the Neolithic Funnel Beaker Culture as suggested by Malmström et al. (2009), as the time period when the mtDNA haplogroup frequency pattern, which is characteristic to the presently living population of Southern Scandinavia, emerged and remained by and large unaltered by the subsequent effects of genetic drift.

As the authors note, the sample sizes were small. But it is odd that all of the Neolithic and Early Bronze Age samples were either U4 or U5a. These lineages now account for only 1–5% and 5–7% of present-day Europeans.

Reference

Melchior, L., N. Lynnerup, H.R. Siegismund, T. Kivisild, J. Dissing. (2010). Genetic diversity among ancient Nordic populations, PLoS ONE 5(7): e11898.
doi:10.1371/journal.pone.0011898

The Roman State and Genetic Pacification

The online journal Evolutionary Psychology has published my article “The Roman State and genetic pacification.” The following is the abstract:

Over the last 10,000 years, the human genome has changed at an accelerating rate. The change seems to reflect adaptations to new social environments, including the rise of the State and its monopoly on violence. State societies punish young men who act violently on their own initiative. In contrast, non-State societies usually reward such behavior with success, including reproductive success. Thus, given the moderate to high heritability of male aggressiveness, the State tends to remove violent predispositions from the gene pool while favoring tendencies toward peacefulness and submission.

This perspective is applied here to the Roman state, specifically its long-term effort to pacify the general population. By imperial times, this effort had succeeded so well that the Romans saw themselves as being inherently less violent than the “barbarians” beyond their borders. By creating a pacified and submissive population, the empire also became conducive to the spread of Christianity—a religion of peace and submission. In sum, the Roman state imposed a behavioral change that would over time alter the mix of genotypes, thus facilitating a subsequent ideological change.

Please feel free to offer your comments.

Reference

Frost, P. (2010). The Roman State and genetic pacification, Evolutionary Psychology, 8(3), 376-389,

 https://journals.sagepub.com/doi/full/10.1177/147470491000800306

A strange story

Eboracum with the Colonia in the foreground and the fortress across the river.

In my last two posts, I presented evidence that Roman York (Eboracum) was home to a large African community in the late 300s. This was due to the stationing of Nubian archers and other African legionnaires in this and other garrison towns of northern England.

Did many remain after the end of Roman rule c. 400? By then, the legions had been largely pulled out and redeployed elsewhere in the dying empire. So the African legionnaires were certainly fewer in number. But these pullouts did not affect the veterans, who were already settled on local estates with their families. Among these ‘Afro-British’ settlers, valued skills like archery would have been passed down from father to son, thus making their community a key player during increasingly troubled times...

What happened after the end of Roman rule? Did this community survive into sub-Roman times? This is the period that began with the last pullout of Roman troops c. 400 and ended with the collapse of Romano-British society in the late 500s.

The historical sources are not entirely mute on this question. These sources, however, have been corrupted by the passage of time. There is also the human temptation to embellish the facts and tell a good story. This is especially so for the sub-Roman period, when many written records were destroyed and when writing itself became almost a lost art. Historical accounts survived only in oral form before being later written down, often much later.

The source that most interests us is the Historia Regum Britanniae (c. 1136), purportedly a translation of an old Welsh chronicle. It is largely consistent with earlier works on British history, like the Historia Britonum (9th-century), the Historia ecclesiastica gentis Anglorum (8th century), and the De Excidio et Conquestu Britanniae (6th century). On the other hand, many of its passages seem too outlandish to be true.

One passage, for instance, reports that over a hundred thousand Africans took part in the struggles between the Romano-British and the Anglo-Saxons:

The Saxons, having had experience of his [the British ruler’s] shiftiness, went unto Gormund, King of the Africans, in Ireland, wherein, adventuring thither with a, vast fleet, he had conquered the folk of the country. Thereupon, by the treachery of the Saxons, he sailed across with a hundred and sixty-six thousand Africans into Britain, which in one province the Saxons by perjuring their oath of fealty, and in another the Britons by continually carrying on civil wars amongst themselves, were utterly laying waste.

Entering into covenant, therefore, with the Saxons, Gormund made war upon Careticus, and after many battles betwixt them, drove him fleeing from city unto city until he forced him into Cirencester and did there beleaguer him.

[…] When Gormund at last had taken and burnt the said city, he did battle with Careticus and drove him fleeing beyond the Severn into Wales. Then he desolated the fields, set fire to all the neighbouring cities, nor did he stint his fury until he had burnt up well-nigh the whole face of the country from sea to sea; in such sort that all the colonies were battered to the ground by rams, and all they that dwelt therein along with the priests of the churches delivered up to the flashing of their swords or the crackling of the flames.

[… after] the tyrant of evil omen had laid waste, as hath been said, well-nigh the whole island with his countless thousands of Africans, the more part thereof which was called Loegria did he make over unto the Saxons through whose treachery he had come into the land. The remnant of the Britons did therefore withdraw them into the western parts of the kingdom, Cornwall, to wit, and Wales […]

Historia Regum Britanniae 11:8-10

If we exclude the African subplot, this story is consistent with other historical accounts, i.e., the Romano-British state fell because of internal dissensions and because the Anglo-Saxons had renewed their war of conquest after a half-century of vassalage.

But did these warring factions recruit soldiers from an African state in Ireland? No such state is described in any other account. On the other hand, the chronicler may have confused Hibernia (Ireland) with Eboracum (York)—the old garrison town where many African legionnaires had once been stationed. The two place names are especially similar if we remember that Eboracum would have been shortened to Ebora in late Latin.

Initially, these Africans may have hired themselves out to opposing Romano-British factions. Then, with the renewal of the Anglo-Saxon invasion, it is possible that many of them defected to that side, having seen which way the wind was turning. Perhaps this mass defection was decisive. Or perhaps the Welsh chronicler needed a scapegoat.

Anyhow, there is no doubt about the final outcome: the Romano-British state collapsed under conditions probably as dramatic as those described above. And it is certainly plausible that some soldiers switched sides. These were chaotic times when people had to live by their wits. In this, the Afro-British were probably no worse than others.

Did their community last into Anglo-Saxon times? This is doubtful. Even without the carnage of war, their numbers would have steadily declined, partly because of the below-replacement fertility that prevailed throughout the Roman Empire and partly because of the 6th-century plagues that carried off one in three people. There was also assimilation: beyond a certain point, successive intermarriage would have led to many individuals passing into the broader Romano-British society.

And, of course, there was the carnage of war. As soldiers, the Afro-British would have suffered many casualties. As civilians, they would have been caught up in the widespread destruction of the late 500s.

If this community did survive into Anglo-Saxon times, there would surely have been some mention by the Venerable Bede [672-735], a prolific Christian writer who lived in Northumbria and often visited York. Yet he made no reference to them.

Or maybe he did. In his commentary on the book of Genesis, he comes down hard on Nimrod, who is often identified by Christian and Jewish commentators as a black African (because his father was Cush):

Genesis 10:8-9a Now Cush begot Nimrod. He began to be mighty on the earth, and he was a stout hunter before the Lord.
While the descendants of Shem and of Japheth remained in the innocence of a life of honesty, there arose from the cursed offspring of Ham one who corrupted the condition of the human way of life by a new kind of living. So long as he was puffed up by his remarkable power, he at first lived by hunting; then, having gathered an army, he strove to exert an unaccustomed tyranny upon the peoples. […]

10:9b From this came a proverb: Like Nimrod a stout hunter before the Lord.
It was turned into a proverb because unaccustomed deeds were done in his times. And the additional phrase, before the Lord, is for the sake of magnifying the outrage, namely that it was totally rash and arrogant that a man should dare to live in such a way on earth ‘before the Lord’.

But then why didn’t Bede mention these Afro-British in his Ecclesiastical History of the English People (Historia ecclesiastica gentis Anglorum)? Perhaps there was a reason for not mentioning them. He had sent an earlier draft to Ceolwulf, king of Northumbria, and asked for the king’s approval. If there had been an alliance between the Anglo-Saxons and Eboracum, Ceolwulf’s family would have been directly involved...

We will never know the full story. (It’s not for nothing that this period is called the Dark Ages). It’s likely that when Roman rule ended c. 400, power fell into the hands of a number of regional entities, including one centered on Eboracum. These entities gradually consolidated to fight the Anglo-Saxon invasion, eventually becoming a single kingdom under a charismatic leader, the semi-mythical “King Arthur.” This leader reduced the Anglo-Saxons to vassalage c. 500, thus bringing about a half-century of peace. Then, after his death c. 550, the Romano-British kingdom split up into warring factions. The Anglo-Saxons seized the opportunity and allied themselves with one or more of the losing factions, including the Afro-British warlords based at Eboracum.

It was an alliance that the Anglo-Saxons lived to regret, apparently because of “unaccustomed deeds.” Perhaps the African soldiers plundered not only Romano-British civilians but also those Anglo-Saxons who had remained in vassalage. Who knows? All we really know, based on archeological evidence, is that Eboracum became uninhabited at some point in the late 500s. And so ends a strange story.

References

Geoffrey of Monmouth. (1904) Histories of the Kings of Britain (Historia Regum Britanniae), transl. by Sebastian Evans

http://www.sacred-texts.com/neu/eng/gem/gem12.htm

Venerable Bede. (2008). On Genesis, transl. by C.B. Kendall, Liverpool University Press.