Razib Khan One-stop-shopping for all of my content

February 21, 2018

The genetics of the Lombard folk migration

Filed under: barbarians,Germans,Lombards,Migration,Roman History,Romans — Razib Khan @ 9:13 am


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.

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