History, Politics And Current Affairs

This is an interesting study, it in particular supports some earlier hypothesis of how the Germanic people and Germanic language originated. Them in turn based on an assortment of earlier genome studies, historical sources, and liguistic analysis.

Full study: https://www.nature.com/articles/s41586-024-08275-2

Abstract
Many known and unknown historical events have remained below detection thresholds of genetic studies because subtle ancestry changes are challenging to reconstruct. Methods based on shared haplotypes1,2 and rare variants3,4 improve power but are not explicitly temporal and have not been possible to adopt in unbiased ancestry models. Here we develop Twigstats, an approach of time-stratified ancestry analysis that can improve statistical power by an order of magnitude by focusing on coalescences in recent times, while remaining unbiased by population-specific drift. We apply this framework to 1,556 available ancient whole genomes from Europe in the historical period. We are able to model individual-level ancestry using preceding genomes to provide high resolution. During the first half of the first millennium CE, we observe at least two different streams of Scandinavian-related ancestry expanding across western, central and eastern Europe. By contrast, during the second half of the first millennium CE, ancestry patterns suggest the regional disappearance or substantial admixture of these ancestries. In Scandinavia, we document a major ancestry influx by approximately 800 CE, when a large proportion of Viking Age individuals carried ancestry from groups related to central Europe not seen in individuals from the early Iron Age. Our findings suggest that time-stratified ancestry analysis can provide a higher-resolution lens for genetic history.

Some parts I’ll comment on:

Our modelling provides direct evidence of individuals with ancestry originating in northern Germany or Scandinavia appearing across Europe as early as the first century CE

The Wielbark archaeological complex has been linked to the later Chernyakhov culture to the southeast and to early Goths, an historical Germanic group that flourished in the second to fifth centuries CE56. Our modelling supports the idea that some groups that probably spoke Germanic languages from Scandinavia expanded south across the Baltic into the area between the Oder and Vistula rivers in the early centuries CE, although whether these expansions can be linked specifically with historical Goths is still debatable.

That lines up very well with what Jordanes wrote in his Getica in the 6th century. He explained that the Goths (and the Gepids which were split off from the Goths) originated in Scandinavia (most likely in Sweden) and sailed across the Baltic sea to initially settle in this exact area (which he called Gothiscandza).

Other genome studies have shown a clear staggered flow out from what is today the southern third of Sweden. One got specific enough to hypothesize that the Germanic culture, and the Germanic languages all originated in eastern Sweden. That is to say the current day Mälardalen area where Stockholm is located in. The linguistic studies can’t narrow it down as closely but several aspects point to southern Scandinavia as the origin of the proto-Germanic language. Such as for instance that the highly conservative Finnish language has preserved a fairly large number of unchanged loan words from proto-Germanic, that there’s no evidence of surviving non-Germanic place names in this area, which both point to proto-Germanic being completely dominant here very early on. Unlike anywhere else.

This Gothic migration out from the area is just one of many though. We’re seeing several waves of Germanic expansion, first within Scandinavia, then radiating in stages onwards to continental Europe and so forth.

A more southern example from this study can be noted here:

In southern Germany, the genetic ancestry of individuals from early medieval Bavaria probably associated with the historical Germanic-language-speaking Baiuvarii59 cannot be modelled as deriving ancestry solely from earlier groups in Iron Age central Germany (P ≪ 1 × 10−36). The Baiuvarii probably appeared in the region in the fifth century CE59, but their origins remain unresolved. Our current best model indicates a mixture with ancestry derived from EIA Peninsular Scandinavia and central Europe, suggesting an expansion of Scandinavian-related ancestry producing a regional ancestry shift (Figs. 2c and 3c

It is however important to note that local populations were absorbed along the way, and the later Germanic tribes that the Romans knew consisted of a more mixed ancestry, and mixed cultures. But the Germanic identity, language, religion (Odin/Wotan etc.) seems to have been key, and the tribes seem to have been aware of their Scandinavian origin later on as well. Jordanes also mention a re-migration by the Heruli into Scandinavia from the continent.

That bring us to the next part:

In EIA Scandinavia (<500 CE), we find evidence for broad genetic homogeneity. Specifically, individuals from Denmark (100 CE–300 CE) were indistinguishable from contemporary people in the Scandinavian Peninsula (Fig. 2c). However, we observe a clear shift in genetic ancestry already in the eighth century CE (Late Iron Age/early Viking Age) on Zealand (present-day Denmark) for which a 100% EIA ancestry model is rejected (P = 1 × 10−17 using Twigstats; P = 7.5 × 10−4 without). This shift in ancestry persists among later Viking Age groups in Denmark, where all groups are modelled with varying proportions of ancestry related to Iron Age continental groups in central Europe (Figs. 3f and 4c).
/…/
These patterns are consistent with northward expansion of ancestry, potentially starting before the Viking Age, into the Jutland peninsula and Zealand island towards southern Sweden. The geographical origin of this ancestry is currently difficult to discern, as the available samples from Iron Age central Europe remain sparse.
/…/

When considered collectively, the individuals who show evidence of central European-related ancestry are mostly observed in regions historically within the Danish sphere of influence and rule. Currently, no such individuals, for example, are noted in eastern central Sweden, which was a focus of regional power of the Svear (Fig. 4a). The difference in distribution could suggest that the central European-related ancestry was more common in regions dominated by the historical Götar and groups inhabiting the lands on the borders of the Danish kingdom.

Note that the Götar has often been thought to have been the origin of the Goths.

So what we have is a migration back of people from continental Europe. The study can’t safely narrow the time down more that between AD 500-1000. But I have a suggestion for what this is, and I think we have two causes for it in the 6th century:

In the year 536 a great volcanic eruption caused disastrous climate changes due to the ash in the atmosphere. There was also likely another eruption in the years that followed, and a plague rummaging around in the aftermath. While the impact was to various degrees worldwide it hit Scandinavia exceptionally hard over a 5-6 year period. Mass starvation due to winter temperatures, ice and snow in the summer with non-existant harvests as a result. About half of the population in Scandinavia died, so a void was created.

The second event I believe was the defeat of the Ostrogothic kingdom in current day Italy in 553 (ish.) My thinking is that remnants of the defeated Ostrogoths decided that the best course of action was to retreat back to their ancestral homeland in Sweden, specifically to the area of their brethren Götar (and some in Denmark). They were likely aware that the population there had been cut in half up there, and that many farms had been completely abandoned, and saw an opportunity to move in there, far away from the reaches of Eastern Rome which had defeated them. The Götar were also probably inclined to accept their ancestral cousins as reasonable replacements to fill out their numbers. The Svear would likely have been less so inclined as they were a different tribe and there seems to have been frequent animosity between them and the Götar, something that would likely have applied to the Goths as well.

Another aspect which may support this is that we know that there was a dramatic change in how battles were fought here between the 6th century and the Viking age. In the 6th century battle was predominantly fought on horseback, only to switch over completely to infantry fighting. It’s hard to explain this change with other than a significant influence from elsewhere. The infantry heavy Ostrogothic army could have been just such an influence. Viking era usage of Roman tactics and formations (such as the Testudo) could also be explained by a transfer from Ostrogoths who remigrated into Scandinavia.

Obviously the above parts are speculative, but I think it might a hypothesis worth trying to explore further.