Genome study reveals what happened after the Roman Empire fell

By Will Dunham

April 29 (Reuters) – The collapse of the Western Roman Empire in AD 476 was a pivotal moment in human history, when the Germanic chief Odoacer dethroned the young emperor Romulus Augustulus in Italy and set in motion the collapse of central authority across much of Europe.

The new research, based on genome data from residents of the fortified Roman frontier in what is now southern Germany, documents how these dramatic political changes affected ordinary people while contradicting the popular view of a “violent “barbarian invasion” sweeping through the former region of the defunct empire.”

For example, researchers have found that the abandonment of marriage restrictions during the empire led to rapid intermixing between the garrison and urban populations of Romans and low-status locals, including some of Northern European descent.

“The temporal correspondence between the collapse of the Western Roman Empire in Italy and the genetic change we detected in southern Germany is extremely precise,” said anthropologist and population geneticist Joachim Burger of Johannes Gutenberg University Mainz in Germany, senior author of the study published Wednesday in the journal Nature.

Researchers analyzed the genomes of 258 people buried in so-called row graves in the present-day German states of Bavaria and Hesse; 112 of them were buried in the Bavarian village of Altheim. Most are dated between 450 and 620 AD.

“Row grave cemeteries were an emerging early medieval burial practice in which individuals were buried in rows, often containing grave goods such as clothing, jewelry and weapons. These cemeteries stretched from the Netherlands to Hungary along the old Roman border,” said Jens Blöcher, population geneticist at Johannes Gutenberg University Mainz and lead author of the study. he said.

Roman authorities had established military outposts to guard against invasions and unrest on the German frontier; Some of these developed into large settlements and eventually cities. These included Mainz, Regensburg, Trier and Cologne, near the burial sites included in the study.

Genome data revealed a major demographic shift that coincided with the disintegration of Roman state structures in the late fifth century. This suggested that people from Northern Europe had moved south into this region in small groups during the long twilight of the imperial period, living separately from the larger Roman population, probably mostly as agricultural labourers. At that time, land could be granted to foreigners under conditions such as restrictions on marriage to Romans.

“They lived there for generations, marrying almost exclusively within their own group and preserving their northern genetic heritage,” Burger said.

MUTUAL MARRIAGE AND INTEGRATION

The Roman military and civilian populations turned out to be genetically diverse, consisting of people with ancestry from various parts of the empire. They were genetically distinct from outsiders who had infiltrated the region from Northern Europe, the Balkans, and even Asia, including places as far away as Britain.

The genomes reflected intermarriage between the two groups after the collapse of the empire and the peaceful integration of peoples that eventually formed a new early medieval society.

“Although we find that people moved from north to south along the old imperial borders, the majority of this migration occurred generations before the tipping point of the end of the empire,” Burger said, adding that this migration “began in the third and fourth centuries.”

“Crucially, this influx was led not by large, ethnically homogeneous tribal blocks or major clans, but by small kin groups or even isolated individuals. This pattern directly contradicts the traditional ‘mass barbarian invasion’ narrative following the fall of Rome,” Burger said.

Long before the overthrow of Romulus Augustulus, the expanding Roman Empire was divided into east and west. While the Western Roman Empire disintegrated after a long period of instability and military setbacks, the Eastern Roman Empire, later called the Byzantine Empire, centered in Constantinople – modern Istanbul – continued to thrive.

Genome data revealed demographic characteristics of the population studied, with a life expectancy of about 40 years for women and 43 years for men and a high infant mortality rate, in a society where almost a quarter of women lost at least one parent by the age of 10.

Christianity was already established as the Roman state religion. Genome data showed that families were monogamous nuclear units, that widows did not remarry within their husbands’ family, and close-consanguineous marriages, such as cousin marriages, were strictly avoided.

“All these features reflect Christian norms from Late Antiquity,” Burger said.

The data show that additional people arrived in the region from the north in the centuries after the collapse of the empire, and that a new genetic profile emerged in the seventh century — “a profile that is very similar to the genetic profile we observe in Central Europe today,” Burger said.

(Reporting by Will Dunham in Washington; Editing by Daniel Wallis)