The barbarian invasions, illuminated by genetics

My own comprehension or understanding of the fall of Rome and the barbarian invasions probably began when I was about nine years old when I read a book about the various peoples who crashed the gates of civilization. First and foremost in the various descriptions were the Huns, a mysterious and fearsome race who in previous times had almost a talismanic role in the history of this period. Like the Mongols later on, they were more a force of nature that illustrated the hand of an angry God in the world than a people with their own agency.

But their identity was, and is, mysterious. Though contemporary descriptions seem to describe them as alien and repulsive in physiognomy, by the 19th century these antique descriptions were filtered through the racialist framework ascendent in the West of that period to cast them as foreign Asiatics. By the 20th century, a reaction set in and attempts to adduce the Huns’ possible connection to Central Asia seem to have diminished, though no one could deny the proposition either.

The fact that the ethnolinguistic affiliation of the Huns is mysterious to us should give a clue that they weren’t related to the standard Germanic or Iranian groups which operated on the fringes of the European Roman world. If the latter surprises you in the context of the European frontier of the Roman Empire, the Sarmatian tribes which pushed into Hungary and harried Rome defenses were related to groups like the Scythians, and branches eventually gave rise to the Alans (who ended up in the North African kingdom of the Vandals!) and Ossetians.* The German peoples have been observed by the Romans since the time of Cimbri invasions, and the later eruptions were easy to slot into that ethnographic framework.

In contrast, the Huns are mysterious precisely because they were a new cultural force. They seemed to be pure nomads like the Sarmatians, but not out of the Iranian steppe cultural milieu. Though they may have been a linguistic isolate, the most likely probability is that they spoke a Uralic (e.g., Hungarian) or Altaic language (e.g., Turkish). Like later steppe nomad hordes which burst out of Inner Asia into the Eurasian oikumene the genius of the Huns was in part organizational, as they accrued to their confederacy a motley of German and Iranian tribes. One standard narrative of the Gothic migrations is that their peregrinations were triggered by the movement of the Huns and their allies to their east and north.

An extreme social constructionist might assert that the term “Hun” simply brackets a new way to organize mobile barbarians beyond the Roman frontier. That they were not ethnically distinct. Though I don’t know anyone who holds to this extreme view, it’s not entirely impossible.

But now we have some genetic data. Population genomic analysis of elongated skulls reveals extensive female-biased immigration in Early Medieval Bavaria:

…we generated genomic data from 41 individuals dating mostly to the late 5th/early 6th century AD from present-day Bavaria in southern Germany, including 11 whole genomes (mean depth 5.56×). In addition we developed a capture array to sequence neutral regions spanning a total of 5 Mb and 486 functional polymorphic sites to high depth (mean 72×) in all individuals. Our data indicate that while men generally had ancestry that closely resembles modern northern and central Europeans, women exhibit a very high genetic heterogeneity; this includes signals of genetic ancestry ranging from western Europe to East Asia. Particularly striking are women with artificial skull deformations; the analysis of their collective genetic ancestry suggests an origin in southeastern Europe. In addition, functional variants indicate that they also differed in visible characteristics. This example of female-biased migration indicates that complex demographic processes during the Early Medieval period may have contributed in an unexpected way to shape the modern European genetic landscape. Examination of the panel of functional loci also revealed that many alleles associated with recent positive selection were already at modern-like frequencies in European populations ∼1,500 years ago.

The admixture plot is key. They have enough markers that intercontinental genetic differences should be discernible. The male and female symbols should be familiar to you, but they also classified the samples by the cranial deformation (a practice associated with the arrival of the Huns to Europe). Blue ~ no deformation, green ~ intermediate, and red ~ deformation.

You can see that the individuals with cranial deformation, who are females, are genetically very distinct from everyone else. And, in particular, the males who exhibit no deformation are pretty homogeneous. Both PCA and admixture suggest that the males resemble typical North-Central Europeans. That is, Bavarians. The women on the PCA plot are shifted toward Southeastern Europe, where anthropologically the deformations were much more common.

The authors analyzed the features of these women and determined that they were likely darker than the males in eye color. This is entirely reasonable in light of their more Southern European genetic character.

There are a few other random samples too. In the admixture plot, FN_2 is a Roman soldier from ~300 AD from the Munich area. About two centuries before the Bavarian samples. The authors note it is curious this individual seems to exhibit Spanish ancestry (IBS being the Spanish samples). And yet this ancestry did not impact the region. Anyone who reads a history of the Roman Empire and its fall and regression knows that the area of southern Germany, Austria, and Hungary south into the Balkans became highly barbarized. It seems likely that many Roman peasants died or fled back to the safety of the empire.

PR_10 is a Sarmatian from the southern Urals. The individual has more “Finnish” ancestry, but that’s not atypical for Russian samples. The South Asian ancestry is something I’d dismiss normally, but I think this might be shared Yamnaya heritage.

Finally, VIM_2, like AED_1108 (a Bavarian female with cranial deformation), has East Asian ancestry. This individual was sampled in Serbia, dates to the 6th century, and is presumably a Gepid, a relatively obscure German tribe.

The presence of East Asian ancestry in these individuals highlights the likely cosmopolitan character of the barbarian zone stretching from Hungary to Bulgaria. It should definitely increase our likelihood that the Huns spoke a Turkic language of some sort. By the time most Turkic peoples arrive on the scene in Western Eurasia, they’re highly admixed, but they invariably have some East Asian ancestry. I highly doubt that the Huns arrived in Europe with the Southern European ancestry, TSI (Tuscan). So that is probably admixture over the century and a half since they arrived that allows for this individual to be predominantly TSI (though the individual may also have been a later Oghuz migrant). The ancestry of the Huns should have been more like a mix of East Asian and Sarmatia. The latter sorts were the first “West Eurasians” they’d run acros unless they had originally come from further south in the Tarim basin.

In the decades before the Huns turned West, they harried the East Roman Empire, pushed its limes back toward the sea, and extorted tribue out of it. After the collapse of Attila’s Empire, they seem to have retreated back to the territories to the east where they could be self-supporting, as opposed to extorting protection money out of states more powerful than them. Because the Huns become less of a problem for the Roman Empire, we don’t hear much about them by the late 5th century. And yet that does not mean they disappeared. The human and biological ecology of this region seems to have been amenable to the intrusion of Eurasian nomads, by the end of the 6th century the Avar confederacy was dominant in the interior Balkans and toward southeastern Germany.

Though this paper is not exactly revolutionary, it confirms that individuals from a post-Hunnic cultural configuration are mostly indigenous, that some evidence of East Asian ancestry persist, it shows that many of the arguments about Late Antiquity as to the ethnological character of peoples will be resolved. Unlike prehistory, where we have no written records, this period has clear and distinct cultures which we have a grasp of. The empty spots on the map are smaller.

* Some captured Sarmatians were settled in Britain on the frontier looking north. There are conjectures that Sarmatian motifs may have influenced Arthurian legends.

The genetics of the Lombard folk migration

There are many debates about the period after the fall of the Western Roman Empire in the late 5th century. For example, did it “fall” in the first place? I believe that the concomitant p0litical, social, and economic changes do warrant that word. But another question concerns the “barbarians,” who were mostly German peoples (there are some exceptions, such as the Iranian Alans and the Huns, whose specific provenance is unclear). Were they ethnically and politically coherent? Were they even peoples?

The extreme stylized positions might be outlined as follows:

– The barbarians who filled the political vacuum after the collapse of the late Roman state were coherent preexistent ethnic and political entities of German origin who migrated en masse and engaged in a folk wandering.

– Though their original provenance may have been in bands of German warriors from specific tribes, but the time they appear on the stage of history as we understand it, the barbarians were in fact a motley crew of opportunists of various origins, who adhered to a “barbarian” identity which was created de novo with the collapse of Rome. They were made by the collapse, they did not cause the collapse.

In the late 1990s, Norman Davies in The Isles presents an argument closer to the latter for the British Isles. That is, the Anglo-Saxon character of Britain was to a large effect a function of elite emulation and diffusion of a Germanic culture introduced by what was operationally a late Roman mercenary class. Davies alludes to texts which indicate a substantial native British population in Anglo-Saxon England centuries after the fall of Celtic kingdoms. This is in contrast to the apocalyptic vision of British monk Gildas, who depicts his Brythonic people fleeing before pagan Saxons and being driven into the sea. And, I have alluded to the possibility that the West Saxon monarchy, which later came to the center of English history during the Viking incursion, was in fact in origin Romano-British, rather than German (the early kings have Celtic names).

And yet England was always the most difficult case for cultural diffusion, because to a great extent Roman-British society did collapse. Both the British Celtic language and Christianity seem to have faded from the landscape, so the that the latter had to be reintroduced by Irish and continental European missionaries. Today, the genetics is more definitive, and it seems a substantial German migration did impact what became England, especially the east, what was the Saxon Shore. Though the majority of the ancestry of the people of England today seems to derive from people who were already resident in Britain in 400 A.D., a substantial enough minority seems to have greater affinities to people who were living in the stretch of land between the Netherlands and Denmark.

The case for mass migration on the continent of Europe (with the exception of much of the Balkans) is more difficult to make in a cut & dried fashion because the basic outlines of Romanness were much more intact in the centuries after the fall than in Britain. Though France and Lombardy may have names which derive from German tribes, there is not much that is German about these regions today, and frankly, even at the height of the barbarian rule when conquest and migration were fresh, the non-Roman overlay was likely a thin elite layer. Outside of Britan and the Balkans, the languages of the Roman Empire and the Christian religion maintained their dominance even after the fall of the Roman political order, a transformation of social norms, and the collapse of the economy.

And yet this does not deny the possibility of migration of peoples into this order. In Empires and Barbarians: The Fall of Rome and the Birth of Europe the historian Peter Heather argues that we must not neglect the likelihood that to some extent the arrival of the Germans was one of “folk wanderings.” That the identity of the Franks, Goths, and Lombards, did not emerge ad hoc and de novo through the accrual of military men around a tiny nucleus of German warlords and their retainers. That women and children were also part of the movement into the Roman Empire. Heather, in fact, depicts the Gothic arrival as one of destitute refugees fleeing the famine and chaos outside of the Pax Romana, and their subsequent militarization and rebellion as one forced upon them by the exigencies of their situation.

A new preprint on bioRxiv, Understanding 6th-Century Barbarian Social Organization and Migration through Paleogenomics, clarify these arguments in the case of the Lombards, who conquered Italy in the 6th century. The abstract:

Despite centuries of research, much about the barbarian migrations that took place between the fourth and sixth centuries in Europe remains hotly debated. To better understand this key era that marks the dawn of modern European societies, we obtained ancient genomic DNA from 63 samples from two cemeteries (from Hungary and Northern Italy) that have been previously associated with the Longobards, a barbarian people that ruled large parts of Italy for over 200 years after invading from Pannonia in 568 CE. Our dense cemetery-based sampling revealed that each cemetery was primarily organized around one large pedigree, suggesting that biological relationships played an important role in these early Medieval societies. Moreover, we identified genetic structure in each cemetery involving at least two groups with different ancestry that were very distinct in terms of their funerary customs. Finally, our data was consistent with the proposed long-distance migration from Pannonia to Northern Italy.

The preprint has genetic and isotopic results from two graveyards associated with elite Lombards of the 6th century. The one in late antique Pannonia would be in modern Hungary. The one in modern Italy is near Turin. The late 6th century was a time of tumult in the Roman Empire, as both Italy and the Balkans were subject to massive turnovers of the ethnic and political orders. The movement into Italy from the northeast was a typical one, prefigured by the Goths and other Germans before the Lombards.

From what I know, as far as German barbarians went, the Lombards were rather “raw” and non-Roman (in contrast, some tribes, such as the Goths and Franks, had had relationships with the Roman Empire for generations before they decided to take it over). Though they were nominally Christianized, and elite Lombards persisted in practicing pagan rituals in Italy down to the 8th century, over 100 years after their conquest of the peninsula.

The authors used a lot of “best of breed” methods with their large data set, but the ADMIXTURE plot really illustrates the result fine enough. The blue is associated with Northwest European ancestry (British and white Utah samples), red with Italian ancestry (Tuscan), and green(ish) with Iberian (Spanish mostly). The very light blue is 1K Genomes Finnish. Panel B is the graveyard in modern Hungary, and panel C is the one from northern Italy.

There is a strong correlation in the graves with those being of Northern European ancestry, and having high status via grave goods. The individuals also exhibited some segregation in the graves. Northern European ancestry and Southern European ancestry individuals were clustered together. The Pannonian individuals, whether Northern or Southern European, don’t seem to resemble ancient or modern Hungarians. The isotope analysis indicates that many of the individuals were highly mobile.

Finally, the data was robust enough to do a pedigree analysis. It looks like a lot of these individuals are related. If you look at the plots you can see groups with the label “Kindred.”

There is so much detail in the results that I won’t recapitulate. Just read the preprint and make sure to check out the supplementary text. What I will say is this.

  1. The Lombard migration seems to have been a migration of people of Northwest European heritage into Southern Europe.
  2. The migration occurred during the lifetime of some individuals. These were highly mobile individuals.
  3. There were associated groups with the Lombards, who were genetically distinct, and likely of lower status. Their Southern European character is also distinct from the native population of Pannonia in the case of panel A.
  4. The Lombards themselves had Northern European ancestry which was somewhat heterogenous (probably different tribes and ethnicities). The shift away from Finnish ancestry probably indicates sampling more from western and opposed to central Europe.
  5. Admixture with the local populations and other post-Roman groups began early on.

The ethnocultural distinctiveness of the Lombards is clear from the textual evidence. The genetic data here confirm that in totality. But, The Geography of Recent Ancestry Across Europe, also highlighted a lot of deep population structure within modern Italy, and could not discern much impact of barbarian migration outside of the Balkans across their data set. Why?

It is rather clear that there were population declines across the West Roman Empire in the years after the Gothic Wars. If you read the textual evidence you imagine some sort of catastrophe going on. In human terms it was catastrophic. On the scale of economics, it was catastrophic. But in terms of population genetics, the long-term impact was not that extreme. The local population structure was not much altered because the Roman population base was so high that even a large decline did not induce bottleneck effects, and the German elite was also small enough it did not much perturb the underlying structure which had roots back to the period before the Roman Empire. Even in the first generations of Lombards in Italy, which is the Collego data set reflects, there was intermarriage between German people and others.

The demographic impact of the German migrations was huge on culture, politics, and economics. But it was not huge on population genetics.

Disruptive ages happen…and they happen fast

A friend of mine was pointing out that there is something of an anti-civilizational polemic in Against the Grain: A Deep History of the Earliest States. It’s the same sort of impulse which also asserts that “Rome never fell it evolved” and that the “Dark Ages” is a myth. I pretty much agree with Scott Alexander’s take. The datum that pollution due to lead did not match that of Classical Antiquity until the early modern period is one I remember as a searing one from The Fall of Rome: And the End of Civilization. You can’t really argue with that.

After reading The Fall of Rome I had a period when I read a lot of stuff on late antiquity. For example Peter Brown’s The Rise of Western Christendom: Triumph and Diversity, A.D. 200-1000. Brown is a serious scholar, and I’ve read several more of his books. But, I do think it shares something with earlier scholarship, and some of the more polemic recent screeds of Rodney Stark (see How the West Won), and that is that Christianity is viewed as a good in and of itself.

That is, if there is one thing that can be said for the period after the fall of Rome, it is that Christianity transcended its Mediterranean focus, and became a truly international religion, and a light unto the nations. If you believe that Christianity is true, then details about population collapse and a recession of cultural productivity matter a lot less than otherwise.

I think the economic historical evidence on the balance does lead to the conclusion that the Roman Empire achieved an optimum of economic development during the Antonine period of the 2nd century A.D. through classical efficiencies on the margin (e.g., specialization through trade, bringing all of the land into production, etc.). These levels were not again reached until after 1000 A.D. in Europe, though comparisons are not entirely apt because innovations such as the moldboard plow and windmills allowed for increases in genuine economic productivity.

The bigger question that looms in the background though is would it have been better to be a median Roman citizen or a median subject of a Dark Age warlord? I don’t have a strong opinion on this, especially when it comes to the ability to consume above subsistence.  It seems likely that the far worst treatment of slaves in places like Sicily than anything serfs were subject to (though serfdom only truly came into its own during the end of the Dark Ages) should be weighed in the calculus, but the Roman peace was also a genuine peace. The petty conflicts persistent at a local level in the Dark Ages may have made the life of a typical peasant less secure than for Roman citizens.

Rather constant reports of subjects and citizens fleeing from strong political units, or more “advanced” nations (e.g., the early American frontier), tell us something real. People valued freedom. But not everyone fled, so we’re probably seeing a bias in terms of who attempted to escape the shackles of civilization (e.g., young able-bodied single men, in particular, loom large in these reports, and I think there’s a reason for that).