A new genetic study has revealed how the arrival of the Visigoths, Suebi and other groups changed the population of the Iberian Peninsula during the early Middle Ages. Researchers found that while these migrations brought new rulers and communities, their demographic impact was far smaller than the population changes that occurred under Roman rule.
An international team of researchers has analysed ancient DNA from 243 individuals buried at 31 archaeological sites across the Iberian Peninsula, covering the period from Roman rule to the eighth century. Their findings, published in the journal Cell, provide new evidence about how migration shaped the population of what is now Spain and Portugal, and how the establishment of early medieval kingdoms affected the people who lived there.
The study, led by researchers from institutions including the Institute of Evolutionary Biology in Barcelona, the Natural Sciences Museum of Barcelona, Harvard University and the University of the Basque Country, found a striking contrast between two periods of major political change. Roman rule brought substantial migration from the eastern Mediterranean and North Africa, creating a genetically diverse population. The arrival of the Suebi, Vandals, Alans and Visigoths from the fifth century onwards introduced new ancestry, but did not fundamentally replace the existing Hispano-Roman population.
“What surprised us most was the contrast between the two processes. Rome created an extraordinarily diverse society due to population movements across the Mediterranean,” says Pablo Carrión, the study’s first author, who completed his doctorate at the Institute of Evolutionary Biology and is now a postdoctoral researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig. “Later migrations introduced new ancestries, but their demographic impact was much smaller.”
How Roman Rule Transformed the Population of Iberia
The Roman conquest of the Iberian Peninsula began during the Second Punic War in the late third century BC, although it took nearly two centuries for Rome to establish control over the entire region. Hispania eventually became one of the empire’s most important territories, supplying agricultural products, minerals and manpower.
Roman rule transformed the peninsula’s political institutions, languages, religion and economy. The new genetic evidence indicates that these changes were accompanied by extensive population movements.
Before the Roman conquest, the available genetic evidence suggests that Iron Age Iberian populations were relatively homogeneous. During the Roman period, however, the population became considerably more diverse, with substantial ancestry originating in the eastern Mediterranean and North Africa.
Of the 66 Roman-period individuals included in one of the study’s ancestry analyses, 55, or approximately 83%, carried eastern Mediterranean-related ancestry. This was particularly prominent in the Ebro River basin and southeastern coastal regions. North African ancestry was also widespread, especially in southern Iberia, where it appeared in nearly all the Roman-period individuals examined.
“Romanisation was not only a political, linguistic and cultural transformation,” explains Carles Lalueza-Fox, director of the Natural Sciences Museum of Barcelona and co-senior author of the study. “Our data show that it was also a major demographic transformation, connecting local populations with human movements originating in different parts of the Mediterranean”.
Interestingly, the researchers found relatively little ancestry directly associated with Italy itself. Instead, much of the new genetic contribution came from the eastern Mediterranean, reflecting the extensive networks of movement that connected the Roman Empire.
The researchers also identified substantial North African ancestry among individuals buried at the early Christian basilica of Cortijo Coracho, near Lucena in southern Spain. Their analysis reconstructed a four-generation family network involving 16 individuals, providing evidence of an established community whose ancestry combined local Iberian, eastern Mediterranean and North African elements.
These findings suggest that migration from North Africa may also have contributed to the spread of religious and cultural practices during Late Antiquity, although the genetic evidence alone cannot establish how Christianity reached the peninsula.
What Happened When the Germanic Kingdoms Arrived?
Map of Europe in AD 420, showing the territories of the late Roman Empire, emerging kingdoms and migration routes, including those of the Visigoths, Vandals and Suebi. Map by Richard Ishida, modified by One2 / Wikimedia Commons (CC BY-SA 4.0).
The political situation changed dramatically during the fifth century. In 409, the Suebi, Vandals and Alans entered the Iberian Peninsula as Roman imperial authority weakened. The Suebi established a kingdom in the northwest, while the Vandals and Alans eventually moved into North Africa.
The Visigoths subsequently became the dominant political force in much of the peninsula, establishing a kingdom that survived until the Islamic conquests beginning in 711.
These developments transformed the political organisation of Iberia. However, historians have long debated how many people actually migrated into the peninsula and whether the new kingdoms represented a major demographic transformation.
The genetic evidence suggests that the newcomers were a relatively small part of the overall population, even though they established powerful ruling groups.
Among 164 individuals dating to the migration and Visigothic periods, the researchers identified 53, approximately 32%, who carried Central-Northern European-related ancestry. Eighteen individuals had ancestry entirely consistent with this genetic component, while others displayed varying degrees of mixture with the existing population.
The strongest concentrations appeared at archaeological sites associated with Germanic material culture, including Pla de l’Horta in northeastern Spain and Los Blanes at ancient Augusta Emerita, now Mérida.
Yet even at these locations, individuals with newcomer-associated ancestry were buried alongside people whose genetic profiles resembled those of the earlier Hispano-Roman population.
The researchers also examined individuals buried at sites without particularly strong associations with Germanic material culture. In this subset, the average Central-Northern European-related ancestry was approximately 12%, suggesting a significant but limited demographic contribution beyond the communities most closely associated with the newcomers.
“The genetic history of the Iberian Peninsula differs from that of other parts of post-Roman Europe,” says David Reich, a geneticist at Harvard University and co-senior author of the study. “We find migration and new ancestries, but not population replacement or large-scale demographic impact”.
This contrasts with developments in Britain, where migrations following the end of Roman rule had a considerably greater effect on the population’s genetic composition.
One of the most remarkable discoveries concerns two individuals who were closely related but buried hundreds of kilometres apart.
Genetic analysis revealed that a woman buried at Hostalot-Ildum, near Vilanova d’Alcolea in Castellón, and another individual buried at Los Blanes in Mérida were siblings. Both possessed entirely Central-Northern European-related ancestry, suggesting that they belonged to a family that had migrated into Iberia.
The two burial sites were separated by approximately 725 kilometres along the Roman road network. Both were associated with distinctive gold pins of a type linked to the Danubian and Pontic regions of Europe.
The researchers suggest that these discoveries may provide evidence of a migration route followed by the Suebi or related groups as they moved across the peninsula during the fifth century.
“We are not simply observing changes in genetic frequencies; we are identifying families who moved across a peninsula that was still connected by the infrastructure of the Roman Empire”, explains Iñigo Olalde, a co-author of the study and Ikerbasque Research Professor at the University of the Basque Country.
The discovery illustrates how ancient DNA can reveal individual experiences behind historical migrations. Although written sources describe the movement of entire peoples, genetic evidence can sometimes identify members of the same family who travelled considerable distances and eventually settled in different communities.
Another intriguing discovery comes from the Los Blanes cemetery in Mérida, where archaeologists had previously uncovered the remains of three young women buried with elaborate grave goods.
Their burials contained gold and silver objects associated with regions of Central and Eastern Europe. Because of these objects and their archaeological context, the women have sometimes been described as Suebian princesses, possibly belonging to the ruling elite during the brief period of Suebian control over Mérida.
However, genetic analysis revealed a more complicated picture. While some individuals buried at the cemetery possessed Central-Northern European-related ancestry, one of the women identified with the Suebian elite had local ancestry. This suggests that belonging to a Germanic ruling group did not necessarily mean that a person, or their ancestors, had migrated from outside the Roman Empire.
The researchers propose that marriages between immigrant elites and established Hispano-Roman families may have helped create political alliances and consolidate power.
The circumstances surrounding the women’s deaths also remain mysterious. They appear to have died young, possibly around the same period, during an era of considerable political instability. The researchers raise the possibility that their deaths were connected to conflicts involving the Suebian and Visigothic kingdoms, although the available evidence cannot establish this.
“These women show how genetics can change our interpretation of past elites: an identity associated with migrant groups, whether Visigothic or Suebian, did not necessarily imply foreign origin, as this could also be acquired through family, political and cultural alliances”, adds Carrión.
The findings demonstrate the importance of combining archaeological evidence with genetic research. Grave goods, clothing accessories and burial customs can reveal cultural connections and social identities, but they cannot always establish where an individual or their ancestors originated.
The study also offers insights into how the newcomers gradually became integrated into Hispano-Roman society.
One potential obstacle was religion. Many of the Germanic newcomers, including the Visigoths, followed Arian Christianity, while much of the Hispano-Roman population adhered to Nicene Christianity. These religious differences may have discouraged marriages between the two communities.
In 589, King Reccared converted to Nicene Christianity, an important development in the history of the Visigothic Kingdom. The researchers examined whether genetic evidence reflected changes in intermarriage before and after this period.
They found that individuals with entirely Central-Northern European-related ancestry were more common in burials dating before Reccared’s reign. In later generations, mixed ancestry became more prominent, suggesting gradual integration with the existing population.
However, the researchers also identified individuals with mixed ancestry dating from before 589, indicating that marriages and relationships between newcomers and local communities had already been taking place.
By the seventh century, the descendants of the migrants were increasingly becoming part of the broader population. Although the newcomers had established kingdoms and introduced new political structures, the demographic foundations of Hispano-Roman society largely survived.
What Happened to the Population After the Visigoths?
The researchers also compared their findings with genetic evidence from later medieval and modern populations. They found that Iberian society during Late Antiquity was considerably more genetically diverse than the present-day population.
This suggests that further demographic changes occurred during the medieval and post-medieval periods, including the Islamic conquests, the expansion of the northern Christian kingdoms and population movements associated with the conquest and resettlement of territories.
The researchers emphasise that more ancient DNA evidence is needed, particularly from northern Iberia and North Africa, to understand these later developments.
“Future studies of mediaeval and post-mediaeval genomes are essential to connect the peninsula’s ancient inhabitants with its present-day populations, with implications for the historical, cultural and even political fields”, notes Lalueza-Fox.
The study highlights an important distinction between political conquest and population change. The Roman Empire profoundly transformed the genetic composition of Iberia through migration across the Mediterranean. The Germanic kingdoms that followed introduced new populations and ancestry, but their demographic impact was considerably smaller.
For historians of the early Middle Ages, the findings provide further evidence that the emergence of new kingdoms did not necessarily mean the disappearance or replacement of the people who had lived under Roman rule.
The article, “Contrasting demographic impacts of Roman colonization and early medieval migrations in the Iberian Peninsula,” is published in Cell. Click here to read it.
A new genetic study has revealed how the arrival of the Visigoths, Suebi and other groups changed the population of the Iberian Peninsula during the early Middle Ages. Researchers found that while these migrations brought new rulers and communities, their demographic impact was far smaller than the population changes that occurred under Roman rule.
An international team of researchers has analysed ancient DNA from 243 individuals buried at 31 archaeological sites across the Iberian Peninsula, covering the period from Roman rule to the eighth century. Their findings, published in the journal Cell, provide new evidence about how migration shaped the population of what is now Spain and Portugal, and how the establishment of early medieval kingdoms affected the people who lived there.
The study, led by researchers from institutions including the Institute of Evolutionary Biology in Barcelona, the Natural Sciences Museum of Barcelona, Harvard University and the University of the Basque Country, found a striking contrast between two periods of major political change. Roman rule brought substantial migration from the eastern Mediterranean and North Africa, creating a genetically diverse population. The arrival of the Suebi, Vandals, Alans and Visigoths from the fifth century onwards introduced new ancestry, but did not fundamentally replace the existing Hispano-Roman population.
“What surprised us most was the contrast between the two processes. Rome created an extraordinarily diverse society due to population movements across the Mediterranean,” says Pablo Carrión, the study’s first author, who completed his doctorate at the Institute of Evolutionary Biology and is now a postdoctoral researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig. “Later migrations introduced new ancestries, but their demographic impact was much smaller.”
How Roman Rule Transformed the Population of Iberia
The Roman conquest of the Iberian Peninsula began during the Second Punic War in the late third century BC, although it took nearly two centuries for Rome to establish control over the entire region. Hispania eventually became one of the empire’s most important territories, supplying agricultural products, minerals and manpower.
Roman rule transformed the peninsula’s political institutions, languages, religion and economy. The new genetic evidence indicates that these changes were accompanied by extensive population movements.
Before the Roman conquest, the available genetic evidence suggests that Iron Age Iberian populations were relatively homogeneous. During the Roman period, however, the population became considerably more diverse, with substantial ancestry originating in the eastern Mediterranean and North Africa.
Of the 66 Roman-period individuals included in one of the study’s ancestry analyses, 55, or approximately 83%, carried eastern Mediterranean-related ancestry. This was particularly prominent in the Ebro River basin and southeastern coastal regions. North African ancestry was also widespread, especially in southern Iberia, where it appeared in nearly all the Roman-period individuals examined.
“Romanisation was not only a political, linguistic and cultural transformation,” explains Carles Lalueza-Fox, director of the Natural Sciences Museum of Barcelona and co-senior author of the study. “Our data show that it was also a major demographic transformation, connecting local populations with human movements originating in different parts of the Mediterranean”.
Interestingly, the researchers found relatively little ancestry directly associated with Italy itself. Instead, much of the new genetic contribution came from the eastern Mediterranean, reflecting the extensive networks of movement that connected the Roman Empire.
The researchers also identified substantial North African ancestry among individuals buried at the early Christian basilica of Cortijo Coracho, near Lucena in southern Spain. Their analysis reconstructed a four-generation family network involving 16 individuals, providing evidence of an established community whose ancestry combined local Iberian, eastern Mediterranean and North African elements.
These findings suggest that migration from North Africa may also have contributed to the spread of religious and cultural practices during Late Antiquity, although the genetic evidence alone cannot establish how Christianity reached the peninsula.
What Happened When the Germanic Kingdoms Arrived?
The political situation changed dramatically during the fifth century. In 409, the Suebi, Vandals and Alans entered the Iberian Peninsula as Roman imperial authority weakened. The Suebi established a kingdom in the northwest, while the Vandals and Alans eventually moved into North Africa.
The Visigoths subsequently became the dominant political force in much of the peninsula, establishing a kingdom that survived until the Islamic conquests beginning in 711.
These developments transformed the political organisation of Iberia. However, historians have long debated how many people actually migrated into the peninsula and whether the new kingdoms represented a major demographic transformation.
The genetic evidence suggests that the newcomers were a relatively small part of the overall population, even though they established powerful ruling groups.
Among 164 individuals dating to the migration and Visigothic periods, the researchers identified 53, approximately 32%, who carried Central-Northern European-related ancestry. Eighteen individuals had ancestry entirely consistent with this genetic component, while others displayed varying degrees of mixture with the existing population.
The strongest concentrations appeared at archaeological sites associated with Germanic material culture, including Pla de l’Horta in northeastern Spain and Los Blanes at ancient Augusta Emerita, now Mérida.
Yet even at these locations, individuals with newcomer-associated ancestry were buried alongside people whose genetic profiles resembled those of the earlier Hispano-Roman population.
The researchers also examined individuals buried at sites without particularly strong associations with Germanic material culture. In this subset, the average Central-Northern European-related ancestry was approximately 12%, suggesting a significant but limited demographic contribution beyond the communities most closely associated with the newcomers.
“The genetic history of the Iberian Peninsula differs from that of other parts of post-Roman Europe,” says David Reich, a geneticist at Harvard University and co-senior author of the study. “We find migration and new ancestries, but not population replacement or large-scale demographic impact”.
This contrasts with developments in Britain, where migrations following the end of Roman rule had a considerably greater effect on the population’s genetic composition.
Two Siblings Buried 725 Kilometres Apart
One of the most remarkable discoveries concerns two individuals who were closely related but buried hundreds of kilometres apart.
Genetic analysis revealed that a woman buried at Hostalot-Ildum, near Vilanova d’Alcolea in Castellón, and another individual buried at Los Blanes in Mérida were siblings. Both possessed entirely Central-Northern European-related ancestry, suggesting that they belonged to a family that had migrated into Iberia.
The two burial sites were separated by approximately 725 kilometres along the Roman road network. Both were associated with distinctive gold pins of a type linked to the Danubian and Pontic regions of Europe.
The researchers suggest that these discoveries may provide evidence of a migration route followed by the Suebi or related groups as they moved across the peninsula during the fifth century.
“We are not simply observing changes in genetic frequencies; we are identifying families who moved across a peninsula that was still connected by the infrastructure of the Roman Empire”, explains Iñigo Olalde, a co-author of the study and Ikerbasque Research Professor at the University of the Basque Country.
The discovery illustrates how ancient DNA can reveal individual experiences behind historical migrations. Although written sources describe the movement of entire peoples, genetic evidence can sometimes identify members of the same family who travelled considerable distances and eventually settled in different communities.
The Mystery of the Suebian Princesses
Another intriguing discovery comes from the Los Blanes cemetery in Mérida, where archaeologists had previously uncovered the remains of three young women buried with elaborate grave goods.
Their burials contained gold and silver objects associated with regions of Central and Eastern Europe. Because of these objects and their archaeological context, the women have sometimes been described as Suebian princesses, possibly belonging to the ruling elite during the brief period of Suebian control over Mérida.
However, genetic analysis revealed a more complicated picture. While some individuals buried at the cemetery possessed Central-Northern European-related ancestry, one of the women identified with the Suebian elite had local ancestry. This suggests that belonging to a Germanic ruling group did not necessarily mean that a person, or their ancestors, had migrated from outside the Roman Empire.
The researchers propose that marriages between immigrant elites and established Hispano-Roman families may have helped create political alliances and consolidate power.
The circumstances surrounding the women’s deaths also remain mysterious. They appear to have died young, possibly around the same period, during an era of considerable political instability. The researchers raise the possibility that their deaths were connected to conflicts involving the Suebian and Visigothic kingdoms, although the available evidence cannot establish this.
“These women show how genetics can change our interpretation of past elites: an identity associated with migrant groups, whether Visigothic or Suebian, did not necessarily imply foreign origin, as this could also be acquired through family, political and cultural alliances”, adds Carrión.
The findings demonstrate the importance of combining archaeological evidence with genetic research. Grave goods, clothing accessories and burial customs can reveal cultural connections and social identities, but they cannot always establish where an individual or their ancestors originated.
Marriage and Integration in Visigothic Spain
The study also offers insights into how the newcomers gradually became integrated into Hispano-Roman society.
One potential obstacle was religion. Many of the Germanic newcomers, including the Visigoths, followed Arian Christianity, while much of the Hispano-Roman population adhered to Nicene Christianity. These religious differences may have discouraged marriages between the two communities.
In 589, King Reccared converted to Nicene Christianity, an important development in the history of the Visigothic Kingdom. The researchers examined whether genetic evidence reflected changes in intermarriage before and after this period.
They found that individuals with entirely Central-Northern European-related ancestry were more common in burials dating before Reccared’s reign. In later generations, mixed ancestry became more prominent, suggesting gradual integration with the existing population.
However, the researchers also identified individuals with mixed ancestry dating from before 589, indicating that marriages and relationships between newcomers and local communities had already been taking place.
By the seventh century, the descendants of the migrants were increasingly becoming part of the broader population. Although the newcomers had established kingdoms and introduced new political structures, the demographic foundations of Hispano-Roman society largely survived.
What Happened to the Population After the Visigoths?
The researchers also compared their findings with genetic evidence from later medieval and modern populations. They found that Iberian society during Late Antiquity was considerably more genetically diverse than the present-day population.
This suggests that further demographic changes occurred during the medieval and post-medieval periods, including the Islamic conquests, the expansion of the northern Christian kingdoms and population movements associated with the conquest and resettlement of territories.
The researchers emphasise that more ancient DNA evidence is needed, particularly from northern Iberia and North Africa, to understand these later developments.
“Future studies of mediaeval and post-mediaeval genomes are essential to connect the peninsula’s ancient inhabitants with its present-day populations, with implications for the historical, cultural and even political fields”, notes Lalueza-Fox.
The study highlights an important distinction between political conquest and population change. The Roman Empire profoundly transformed the genetic composition of Iberia through migration across the Mediterranean. The Germanic kingdoms that followed introduced new populations and ancestry, but their demographic impact was considerably smaller.
For historians of the early Middle Ages, the findings provide further evidence that the emergence of new kingdoms did not necessarily mean the disappearance or replacement of the people who had lived under Roman rule.
The article, “Contrasting demographic impacts of Roman colonization and early medieval migrations in the Iberian Peninsula,” is published in Cell. Click here to read it.
Top Image: Illustrations suggesting a possible reconstruction of the Suebian princesses. Image © Joaquín Suárez
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