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.