Slavic Migration's Impact on Central, Eastern Europe

Genetic analyses of medieval human remains reveal large-scale migrations, regional diversity, and new insights into early medieval communities

To the point

• Dramatic population change: Analysis of genome-wide data from more than 550 ancient individuals demonstrates that, during the 6^th-8^th centuries CE, Eastern Germany, Poland/Ukraine, and the Northern Balkans experienced a major shift in ancestry, with over 80 percent originating from eastern European newcomers.
• Support from other analysis: An independent study of 18 genomes from the South Moravian region linked to one of the first Slavic-speaking polities confirms this pattern.
• Regional differences: While genetic turnover was nearly complete in the north, regions like the Balkans saw more mixing between Eastern European incomers and local communities. This diversity of ancestries persists until today in the modern populations of these areas.
• Integration, not conquest: Genetic evidence shows no sex bias in the migration-entire families and communities seemed to have moved and integrated, rather than just male warriors.
• Flexible social structure: In Eastern Germany, the migrants brought a new way of social organization, visible in the formation of large patrilinear pedigrees-a stark contrast to the much smaller family units typical of the preceding Migration Period. Meanwhile, in Croatia, early immigrant communities appear to have maintained more traditional or regionally continuous social structures, with less dramatic changes from the patterns seen before the demographic shift.

The spread of the Slavs stands as one of the most formative yet least understood events in European history. Starting in the 6th century CE, Slavic groups began to appear in the written records of Byzantine and Western sources, settling lands from the Baltic to the Balkans, and from the Elbe to the Volga. Yet, in stark contrast to the famous migrations of Germanic tribes like the Goths or Langobards or the legendary conquests of the Huns, the Slavic story has long been a difficult puzzle for historians of the European Middle Ages.

This is partly because early Slavic communities left behind rather little for archaeologists to find: they practiced cremation, built simple houses, and produced plain, undecorated pottery. Perhaps most significantly, they did not leave behind written records of their own for several centuries. As a result, the term "Slavs" itself has been ambiguous, sometimes imposed by outside chroniclers and often mis-used in later nationalist or ideological debates. Where did these people come from, and how did they so thoroughly change the cultural and linguistic map of Europe?

Historians have long debated whether the spread of Slavic material culture and language was driven by a mass migration of people, the gradual "Slavicisation" of local populations, or a combination of both. But the evidence was thin-especially in the crucial early centuries, when cremation made DNA studies nearly impossible and archaeological traces were modest.

How the Slavs transformed Europe

Now, an international research team of researchers from Germany, Austria, Poland, Czechia and Croatia led by the HistoGenes consortium and working in close cooperation with the State Office for Heritage Management and Archaeology Saxony-Anhalt, has provided answers with the first comprehensive ancient DNA study of medieval Slavic populations. By sequencing over 550 ancient genomes, the team has revealed that the rise of the Slavs was, at its core, a story of people on the move. Their genetic signatures point to an origin in the region stretching from southern Belarus to central Ukraine-a geographic area that matches what many linguistic and archaeological reconstructions had long suggested. "While direct evidence from early Slavic core regions is still rare, our genetic results offer the first concrete clues to the formation of Slavic ancestry-pointing to a likely origin somewhere between the Dniester and Don rivers" says Joscha Gretzinger, a geneticist from the Max Planck Institute for Evolutionary Anthropology in Leipzig and lead author of the study.

The data show that, beginning in the 6th century CE, large-scale migrations carried this Eastern European ancestry across wide areas of Central and Eastern Europe, which caused the genetic makeup of regions like Eastern Germany and Poland to shift almost entirely. Yet the expansion did not follow the model of conquest and empire: Instead of sweeping armies and rigid hierarchies, the migrants built their new societies on flexible communities, often organized around extended families and patrilineal kinship ties. Also, this was not a single, uniform model across all regions. In Eastern Germany, the shift was profound: large, multi-generational pedigrees became the backbone of society, with kinship networks more extensive and structured than the small nuclear families seen in the preceding Migration Period. In contrast, in areas such as Croatia, the arrival of Eastern European groups brought much less disruption to existing social patterns. Here, social organization often retained many features of earlier periods, resulting in communities where new and old traditions blended or persisted side by side. This regional diversity in social structure highlights how the spread of Slavic groups was not a one-size-fits-all process, but rather a dynamic transformation that adapted to local contexts and histories.

"Rather than a single people moving as one, the Slavic expansion was not a monolithic event but a mosaic of different groups, each adapting and blending in its own way-suggesting there was never just one 'Slavic' identity, but many." explains Zuzana Hofmanová from the MPI EVA and Masaryk University in Brno, Czechia, one of the senior lead authors of the study. Notably, the genetic record reveals no significant sex bias in these migrations: entire families moved together, and both men and women contributed equally to the emerging societies. More data will show in the upcoming years how each community adapted, integrated, or reinvented itself in response to both migration and its own local history.

Spotlight on Eastern Germany

In Eastern Germany specifically, the genetic data show an especially striking story. Following the decline of the Thuringian kingdom, more than 85 percent of the ancestry in the region can be attributed to new arrivals from the East. This marks a shift from the earlier Migration Period, when the population was a cosmopolitan mix as best illustrated by the site of Brücken, a richly furnished late antique cemetery from Sachsen Anhalt that displayed a mix of Northern, Central and Southern European ancestry. With the spread of the Slavs, this diversity gave way to a population profile almost identical to modern Slavic-speaking groups in Eastern Europe. Archaeological evidence from cemeteries confirms that these new communities organized themselves around large extended families and patrilineal descent-while women of marriageable age typically left their home villages to join new households elsewhere. Notably, the genetic legacy of these early Eastern European settlers endures today among the Sorbs, a Slavic-speaking minority in Eastern Germany. Despite centuries of surrounding cultural and linguistic change, the Sorbs have retained a genetic profile closely related to the early medieval Slavic populations that settled the region more than 1,000 years ago.

Spotlight on Poland

In Poland specifically, the research overturns earlier ideas of long-term population continuity. Genetic results show that starting in the 6th and 7th centuries CE, the region's earlier inhabitants-descendants of populations with strong links to Northern Europe and Scandinavia in particular-almost entirely disappeared and were successively replaced by newcomers from the East, who are closely related to modern Poles, Ukrainians, and Belarusians. This conclusion is reinforced by the analysis of some of the earliest known Slavic inhumation graves in Poland, excavated at the site of Gródek, which provide rare and direct evidence of these early migrants. While the population shift was overwhelming, the genetic evidence also reveals minor traces of mixing with local populations. These findings underscore both the scale of population change and the complex dynamics that shaped the roots of today's Central and Eastern European linguistic landscape.

Spotlight on Croatia

The Northern Balkans specifically present a different pattern compared to the northern immigration area-a story of both change and continuity. Ancient DNA from Croatia and neighboring regions reveals a significant influx of Eastern European-related ancestry, but not a complete genetic replacement. Instead, Eastern European migrants mixed with the region's diverse local populations, creating new, hybrid communities. Genetic analyses indicate that in present-day Balkan populations, the proportion of this incoming Eastern European ancestry varies considerably but often makes up roughly half or even less of the modern gene pool, highlighting the region's complex demographic history. The formation of such a mixed community is clearly seen at the site of Velim, where some of the oldest Slavic burials in the region show evidence of both Eastern European migrants and up to 30% local ancestry. Here, the Slavic migration was not a wave of conquest but a long process of intermarriage and adaptation, resulting in the cultural, linguistic and genetic diversity that still characterizes the Balkan Peninsula today.

Independent confirmation in Moravia, Czechia

In an independent study at the same time today published in Genome Biology, supported among others by Czech projects FORMOR and RES-HUM, researchers from Czechia, Germany, Switzerland and UK with a senior leader of Dr. Zuzana Hofmanová found that there was also a population change in Southern Moravia (Czechia) and that also this demographic shift can be linked to the change to the Slavic-associated material culture which originated in modern-day Ukraine. While whole genomes of preceding, Migration-period individuals showed a large genetic diversity, individuals linked with the Slavic-related cultural horizons had affinities to Northeastern Europe, a feature that was not present before.This dataset included an individual, an infant, buried within a very early Slavic context usually only linked to cremations thus narrowing regionally the change in time and associating it to the Prague-Korchak culture. Importantly, the same genetic signal was present not only for individuals from 7th and 8th centuries but was regionally continuous to 9th and 10th century when this region is associated to one of the earliest Slavic polities, Moravian principality, known because of Saints Cyril and Methodius and the first literary Slavic language (Old Church Slavonic) and Glagolithic script they created for their mission among the Moravian Slavs.

A new chapter in European history

This study does not just resolve the historical puzzle how one of the world's largest linguistic and cultural groups came to be. It also offers new perspectives on why Slavic groups spread so successfully, and why they left so few traces of the kinds historians once sought:

As Walter Pohl, one of the senior lead authors of the study and medievalist at the Austrian Academy of Sciences, puts it, the Slavic migration represents a fundamentally different model of social organization: "a demic diffusion or grass-root movement, often in small groups or temporary alliances, settling new territories without imposing a fixed identity or elite structures." Their success may have been due not to conquest but to a pragmatic, egalitarian lifestyle-one that avoided the heavy burdens and hierarchies of the crumbling Roman world. In many places, the Slavs offered a credible alternative to the declining empires around them. Their social resilience, relatively simple subsistence economy, and willingness to adapt made them well-suited to periods of instability, whether caused by climate change or plague.

The new genetic findings support this interpretation. Mostly where early Slavic groups are found in the archaeological and historical record, their genetic traces match: a common ancestral origin, but regional differences shaped by the degree of mixing with local populations. In the north, earlier Germanic peoples had largely moved away, leaving room for Slavic settlement. In the south, the Eastern European newcomers merged with established communities. This patchwork process explains the remarkable diversity found in the cultures, languages, and even the genetics of today's Central and Eastern Europe. "The spread of the Slavs was likely the last demographic event of continental scale to permanently and fundamentally reshape both the genetic and linguistic landscape of Europe." says Johannes Krause, director at the Max Planck Institute for Evolutionary Anthropology and one of the senior authors of the study.

With these new results, researchers can finally see beyond the gaps in the written and archaeological record to trace the true scope of the Slavic migrations-one of the most influential yet understated chapters in Europe's past. The echoes of this history remain today, in the languages, cultures, and even the DNA of millions across the continent.