The Avars, mysterious horse-riding warriors who helped hasten the end of the Roman Empire, dominated the plains between Vienna and Belgrade, Serbia, for more than 2 centuries. Then, they vanished without a trace. Scholars have been searching for their origins ever since. Now, archaeological and genetic evidence reveals the Avars were migrants from Mongolia — and their migration was, up to that point, the fastest long-distance movement in human history.
The Avars had no written records. Grave goods and historical accounts suggest they dominated the plains of modern-day Hungary soon after their arrival in Europe about 1500 years ago. They interred their elites in massive burial mounds, surrounded by weapons, and finely decorated gold and silver vessels. They were often buried with horses and riding equipment. (The earliest stirrups in Europe are from Avar graves.)
It was those elaborate burials that yielded clues to the Avars’ origins. An international team of researchers extracted ancient DNA from the skeletons of a dose of high-status men and women buried in 27 sites from modern-day Hungary. Comparing that DNA with existing ancient DNA data, the team found the closest matches came from graves from the sixth century in what is today Mongolia, they report today in Cell.
“Genetically speaking, the elite Avars have a very, very eastern profile,” says Choongwon Jeong, a co-author and geneticist at Seoul National University.
The first Avars burials were a near-identical match for an individual buried just a few decades earlier in eastern Mongolia, showing the first Avars in Europe probably made the journey of almost 7,000 kilometers themselves. They are likely to capitalize on their nomadic lifestyle, trade networks stretching across the vast steppe, and horse-riding prowess to move quickly across the grasslands of Eurasia. “The DNA is so close it’s got to be within one generation, or less,” Jeong says.
That genetic data backs up two historical accounts of the Avar’s origins. One sixth century Chinese source describes an enigmatic steppe people called the Rouran, one of many horse-riding nomadic groups that swept out of the Mongolian steppes to attack their northern borders. The Rouran’s grassland empire was reportedly defeated by rival nomads in 552 CE
A continent away, and just 15 years later, diplomats from Byzantium, the eastern remnants of the once-mighty Roman Empire, reported the arrival of a new group from the east on the shores of the Caspian Sea. and claimed to be related to a far-off people known as the Rouran. But was their origin story true, or just a boast?
The new genetic data seem to answer that question, says Walter Pohl, a historian at the University of Vienna. “We have a very clear indication that they must have come from the core of the Rouran Empire. They were the neighbors of the Chinese. ”
After their arrival on the fringes of the Roman Empire, the Avars pushed into central Europe, conquering the plains along the Danube River between modern-day Vienna and Belgrade, and even laying siege to Constantinople, now Istanbul, in 623 CE They were finally defeated by Charlemagne — a king whose bigger, better army destroyed their capital and eventually united now of Europe for the first time in centuries — in the late 700s.
To find out more about the structure of Avar society, the researchers compared Avar graves from different time periods, locations, and social strata. Both their graves and their genes suggest those at the top of Avar society were a tight-knit group. DNA from elite burials in the early 700s still showed East Asian characteristics, suggesting the elites didn’t mix with the local European population. Less ornate burials farther from the kingdom’s center, meanwhile, show more mixed ancestry.
“The nonelite is probably mixed with the local population,” says Guido Gnecchi-Ruscone, a population geneticist at the Max Planck Institute for Evolutionary Anthropology, “but it seems the elite stayed homogenous.”
Genetic evidence also suggests the group that moved from Mongolia to Hungary was much larger than the researchers anticipated. Had the invaders been just a tiny band of warriors and their wives, their descendants would have shown strong genetic signals of inbreeding after 2 centuries. But there are no such signals, even as now of the remains studied from elite graves maintain a strong East Asian signature. That suggests the population was tens of thousands strong, Pohl says, or that more migrants from their homeland kept joining the Avar in Europe for decades after their first conquests.
Archaeologists say the multidisciplinary study is a welcome departure from research that looks narrowly at genetic data to make sweeping claims about past migrations. “They’re trying to look into finer social issues and time scales, and that’s the direction we should be going,” says Bryan Miller, an archaeologist at the University of Michigan’s Ann Arbor. “It’s the kind of paper a genomics paper should be.”
What happened after the Avars’ defeat at the hands of Charlemagne remains unclear. Their genetic signature soon dwindled to almost nothing in the regions they once ruled, Gnecchi-Ruscone says. “Something happened, but we don’t know what — do they move? Are they simply overwhelmed by the local population? That’s one of the things we want to find out. ”