Until recently, most major ancient DNA analyses of the Roman Empire have focused on the ancestry of ancient Romans in the Italian Peninsula and Britain. But this year, researchers turned their attention to the ancestry of ancient Romans in the Balkan Peninsula, instead. Reporting their results in Cell this month, the researchers revealed that the occupants of this Roman frontier received relatively little genetic influence from the Roman heartland.
“Ancient DNA can give a lot of insight into historical periods, especially for regions where historical sources are scarce or when we don’t know whether sources are biased or not,” says Iñigo Olalde, a population geneticist at the University of the Basque Country and a researcher involved in the analysis, in a press release. “For example, most historical sources from the Balkans are written from the side of the Romans.”
According to the researchers, the results reveal that the ancestry of the region was not forged through the movement of Iron Age Italians from Italy, but through some other mechanism.
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What Is the Roman Empire?
The Roman Empire was massive. Comprised of around 50 to 90 million inhabitants at its apex, which was then around a fifth of the world’s population, what was seen as “Rome” stretched from the shores of Britain to the Black and Caspian seas.
With its Mediterranean core, Rome spanned almost 2 million square miles. But while ancient Romans traveled throughout the Mediterranean world, ancient DNA analyses haven’t always had the same reach.
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Roman Rule in the Balkan Peninsula
The Balkan Peninsula served as a “crossroads” for the Roman Empire, connecting over 1,000 miles of military and communication infrastructure that crisscrossed the European continent, according to the researchers. Experiencing rapid “Romanization” following the establishment of Roman rule in the first century C.E., the area also acted as an important cultural center until the sixth and seventh centuries C.E., when imperial control over the area started to collapse.
Who Were the Balkan People?
Though the Roman influence on the populations of these crossroads has been investigated through the frames of politics, commerce, and culture, the impacts of Roman imperialism on the ancestry of those populations hasn't been studied as much.
In fact, though recent research has investigated the genetics of the ancient Roman Empire, much of this research has focused on Italy and Britain. Less is known about the genes of the people in other frontiers, and far less about those of the people in the Balkans.
“This region was one of the distant frontiers of the Roman Empire, which makes it interesting to study,” says Olalde in the release. “This is clearly a place where you would expect people to come in contact with people from outside the empire, so you can test things such as globalization.”
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What Was Rome’s Genetic Impact in the Balkans?
Researchers assessed DNA from 136 ancient individuals from 20 ancient sites across the Balkans. Between the Danube and Sava rivers to the north and the Adriatic, Mediterranean, and Aegean seas to the south, the researchers explored the empire’s genetic impacts on the region.
The individuals lived between 1 and 1000 C.E., experiencing the early years of the empire (1 to 250 C.E.), the later years of the empire (250 to 550 C.E.), and the weakening (and eventual end) of the empire in the west (550 to 1000 C.E.). They were interred in sites that ranged from urban to rural, including several military settlements.
To the researchers’ surprise, no signs of Iron Age Italian ancestry were identified in individuals from each stage of the empire. That being said, ample signs of ancestry from Western Anatolia, Central, Northern, and Eastern Europe, and the Pontic-Kazakh Steppe were identified, revealing a flood of migrations into the Balkan Peninsula from all around the ancient world.
Balkan Migrations in the Early and Late Empire
Specifically, the remains revealed that a stream of migrants from Western Anatolia moved into the Balkans during the early years of the empire, while a wave of migrants with mixed ancestry made their way to the area during the empire’s later years. The mixed ancestry of the latter migrants, which included ancestry from Central and Northern Europe and the Pontic-Kazakh Steppe in Eastern Europe and Central Asia, suggests they traveled as a multi-ethnic entity, or “confederation.”
An outlier among the individuals from these two stages of empire, the researchers also identified the remains of a 16-year-old boy in Viminacium, an ancient city in what is now Serbia. The boy ate an unusual diet for the area and possessed 100 percent East African ancestry.
“This individual clearly grew up outside the borders of the Roman Empire,” says Carles Lalueza-Fox, a paleogenomicist at the Institute of Evolutionary Biology in Spain and another member of the research team, according to a press release.
Balkan Migrations in the Imperial Aftermath
Further research revealed a major movement of Eastern European individuals into the Balkans following the fall of Roman imperialism in the west. According to the researchers, this movement is the most recent major migration to occur in the region, and it coincides with recorded migrations of Slavic-speaking people from Eastern Europe starting around 700 C.E.
“We found this genetic signal of Slavic migration all across the Balkans,” says Lalueza-Fox in the release. “This could have important social and political implications given that the Balkans has had a long history of conflict associated with their perceived identities.”
Slavic Speaking and Ancestry in the Balkans
Since this major migration, the individuals in the Balkans have had a consistent ancestral composition. In fact, the Slavic migrations from the 700 C.E. onwards account for around 30 to 60 percent of the ancestry of the people in the Balkans today.
“There have been debates about how impactful these migrations were and to what extent the spread of Slavic language was largely through cultural influences or movements of people, but our study shows that these migrations had a profound demographic effect,” says David Reich, a population geneticist at Harvard University and senior author of the research, in a press release. “More than half of the ancestry of most peoples in the Balkans today comes from the Slavic migrations.”
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The Future of Ancient DNA Research in the Balkans
Improvements in ancient DNA analysis are inspiring the researchers to continue their investigation into the Balkans, in an attempt to reveal the specific interactions of the occupants of the region.
“We are now able to sequence hundreds of individuals from the same site, so we can go to another level of resolution and start to understand more about the social interactions and kinship between the different individuals,” says Olalde in the release.
Still, with these additional analyses or without, it’s clear that the region was molded by migrants from several swaths of the empire, except — it now seems — its center.
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