DNA Study of Post-Roman Europeans Reveals Emergence of Complex New Society

Pictured in this collection of grave items from Szeleste are the center of a shield, or umbo (upper right), various brooches (center), mosaic beads, and an antler comb (top left). Credit: Savaria Museum, Szombathely, Hungary.

The fall of the Roman Empire led to a tumultuous period of political, demographic and cultural change in Western Europe from 4th to 6th centuries in the Common Era (CE). A new study that uses ancient human DNA analyses combined with archeological finds is helping scientists to frame a better picture of the Early Medieval people who inhabited Western Europe and the societies they created. Their findings are explained in a paper published in Science.

As part of an international and multidisciplinary team, Stony Brook University's Krishna R. Veeramah, an associate professor in the Department of Ecology and Evolution, and lead authors Yijie Tian (SBU) and István Koncz (Eötvös Loránd University, Hungary) sequenced more than 300 genomes from historical Hungarian cemeteries. By analyzing individuals who lived from the late Roman era to the early Middle Ages, the team aimed to uncover how regional societies developed in these lands after the fall of the Roman Empire.

Despite its importance in laying the foundations of modern Europe, we know little about this era, which is commonly associated with the migration of so-called "Barbarians" - essentially various groups from other areas of Europe and Asia who took over much of Europe as the Roman Empire disintegrated. These Barbarian kingdoms left very few written records, leaving historians and archeologists to rely on the viewpoints of the conquered Romans.

This close-up shows a bow brooch, which was used to fasten cloaks, tunics, or other fine clothing. Credit: Savaria Museum, Szombathely, Hungary.

The research team generated a combined ancient DNA and archaeological dataset to reconstruct post-Roman era organization in the Little Hungarian Plain, an area in northwestern Hungary that was part of Pannonia, an important Roman province lying on the border of the former Empire. They selected seven cemetery sites that provided access to various skeletal remains for DNA sequencing and archeological characterization. The sites included five from the post-Roman era and two from the Roman era.

Overall, they discovered that during the Roman period, communities in the region formed part of a dense infrastructural and collaborative network, with populations showing a predominantly southern European genetic ancestry, but also with the notable presence of genetic diversity from Asia and Africa, representing the cosmopolitan nature of the Roman Empire.

However, the post-Roman sites exhibited a rise in northern European genetic ancestry, reflecting large-scale population movements into the region. By integrating their genomic data with archeological material, the researchers surmised that the influx of individuals with northern European ancestry likely reflected the historically documented - yet debated - expansion of the Lombard Kingdom from north of the Danube River into former Roman territories during the early 6^th century. They determine this movement was not due to a single large-scale migration but rather to complex and sustained patterns of mobility, with genetic connections linking individuals in the Little Hungarian Plain to populations farther north. They also found that these new communities did not just establish loose rural settlements but created a diverse, hierarchical new society consisting of ruling elites forging a new post-Roman polity.

"Prior to our ability to analyze the DNA of these peoples who moved into what is now Hungary, and similar regions in Europe, archeologists assumed these communities were of the same rural type, but what we see is a larger post-Roman society," said Veeramah, co-corresponding author. "While we found the same overall genetic diversity in multiple cemeteries in the region, the groups appear to have very different social structures based on ancestry and grave goods."

For example, he explained that in one of the cemeteries, Hegykő, the researchers identified that this newly arriving population from northern Europe formed relatively large, interconnected kinship groups who appeared to have an elevated status based on their better diets and richer grave goods like weapons and brooches. This suggests they were an elite band that came into the region and exerted some kind of political control. In contrast, at the neighboring site of Szeleste, they did not see the same kind of close kinship ties, and there were families and groups with mixed northern and southern ancestry, suggesting a much less hierarchical and elite-oriented society.

The Lombards and an evolving new society

According to the team, the genetic analyses clearly support the influx of a new population, probably under Lombard authority but drawn from a wide swath of more northerly regions beyond the borders of the former Roman Empire to what is now Hungary and central Europe.

Their findings also show that in the Little Hungarian Plain - though the migrating Lombards eventually became the ruling power - multiple modes of community formations were shaped by interactions between incoming groups with mainly northern European ancestry and local populations with predominantly southern European ancestry, all helping to form a new, complex society.

The research is part of a larger project, HistoGenes, funded by the European Research Council (ERC) that includes Veeramah and his team. This multidisciplinary group of geneticists, archaeologists, historians and anthropologists have analyzed more than 6,000 individuals who lived in Central Europe between 400 and 900 CE.

Professor Patrick Geary of the Institute for Advanced Study, co-PI of HistoGenes, adds, "The project has revealed both gradual and localized forms of movement across short and long distances, as well as rapid, large-scale population shifts from Eastern Asia into the Carpathian Basin. It has also demonstrated that material culture and genetic ancestry do not necessarily coincide and has illuminated the diverse ways newcomers integrated into existing populations."