Empires of old are shrouded in mystery and are the subject of intense historical investigation. Given the enormous time scales and the lack of written records, accurate details of most founders of these empires have been lost to the vagaries of oral history. Many of them have been turned into legends, their life stories left to be pieced together from various fables.
Some scholars have held that most ancient empires started out as smaller nomadic groups that went on to assimilate various tribal units, under the leadership of a small, elite nucleus often made up of certain families. These elite individuals and the societies they shaped bonded through war, disease outbreaks, and large-scale migration to lay the foundations of large protectorates.
They are now being slowly brought into view by items from graves at archaeological sites, including the remains of human burials and silver, gold, and other artefacts, and the increasingly advanced tools and methods scientists are using to pry their secrets from them.
A new view of history
Palaeogenomics — the analysis of ancient DNA from archaeological sites — is an important way for scientists to understand the past. For example, they have investigated the genomes of individuals from the now-extinct Paleo-Eskimo, the first culture known to settle in Greenland, to reveal their migration from Siberia to the New World around 5,500 years ago. Ancient DNA from the world’s tropical regions has been a challenge to study because the skeletal remains that host them decay rapidly in the warm, wet weather. Nevertheless, advances in palaeogenomics allowed researchers to obtain and sequence the genome of a 4000-year-old strand of hair belonging to an individual from the Middle Nile Valley in eastern Africa, allowing them to unravel the history of population dispersal on the continent.
Studies involving human DNA from the Bronze Age in Eurasia have provided clues about the routes along which people migrated, how their various cultures and languages mixed, and even how some of them developed lactose intolerance.
Palaeogenomics has significantly improved our knowledge of human evolution, spread, and development. To recognise his efforts to establish this discipline, Svante Pääbo received the Nobel Prize in Physiology or Medicine in 2022.
The Avar and the Xiongnu
Today, researchers are able to elicit from ancient DNA particular details about ancient human societies as well. For example, the Avars, a mysterious group of horse-riding warriors, ruled vast swaths of modern-day Hungary, Romania, Slovakia, Austria, and Serbia for more than two centuries. They helped end the Roman empire and dominated large parts of Europe in the 6th century AD.
Their origins have been unclear and a topic of intense debate among genomics scholars. Some believe the Avars migrated from Mongolia and were successors of the Mongolian Steppe Rouran empire. After a resounding defeat at the hands of the Turks, they travelled west into Europe, where they held sway for over 200 years.
However, the start of this history is blurry at best because historical records from the 5th and 6th centuries provide contradicting information about where the Avars came from.
To crack this puzzle, an international team of researchers examined some items at gravesites created before and after the Avars arrived in Europe. The sites founded by Avar communities in Europe had large burial mounds surrounded by gold earrings, pendants, bracelets, gold and silver vessels, swords, weapons, and horse-riding equipment, indicating the elite status of the buried individuals. By examining the skeletal remains of these individuals, the researchers determined that the genetic compositions of pre-Avar individuals was closer to those of present day central and eastern Europeans — whereas the genomes of the Avar elite closely matched individuals laid to rest in the 6th century in Central Asia.
Thus it was clear that the Avars were originally from Mongolia and that they migrated more than 7,000 km across the vast grasslands of Asia within a single generation. The lack of inbreeding among the buried Avar individuals also suggested the Avar migration party probably consisted of thousands of individuals, not just a few elites. This long distance trans-Eurasian movement was one of the fastest in ancient times.
Further investigations of gravesites created over a period of time revealed the Avar genetic material had intermixed with the local population. That is, the Avar non-elite probably interbred with the local population even as their rulers placed a premium on not doing so.
The findings were published in April 2022 in Cell.
A study published a year later, in Science, took a similarly close look at members of the Xiongnu empire, among the first of many nomadic steppe kingdoms that arose in Eurasia and ruled over large parts of Central Asia. These members belonged to both nomadic and sedentary groups of people from diverse ethnic backgrounds, led by an aristocratic elite group. Palaeogenomic studies at Xiongnu burial sites revealed high genetic diversity in individuals occupying the lower strata of their society, implying diverse origins. The aristocrats on the other hand had lower genetic diversity as well as Eurasian ancestry.
The story of the Longobards
In the fifth century AD, the Roman Empire collapsed. The Longobards, a tribe from an area that we today call Germany, had a large influence on post-Roman social dynamics, reflected in their genetic diversity. The Longobards moved from Germany’s north to the south and conquered the area around present-day Austria and Slovakia. From here, they moved quickly to invade northern Italy, which had been severely depopulated after a long war. Together with a large number of other tribes the Longobards finally invaded all of Italy to establish a kingdom that ruled for over 200 years.
Studies of the remains of Longobard elites have found that close-knit relationships among these individuals may have played an important part in maintaining their society.
On August 19, the Proceedings of the National Academy of Sciencespublished a study authored by an international group of researchers, led by Stony Brook University in New York. It described ancient DNA from 28 elite gravesites plus 24 previously sequenced genomes associated with the Longobards. They combined palaeogenomics with archaeological and isotopic data to piece together social interactions, burial customs, and dietary habits among the Longobards.
They reported that the community was organised around a few related elite individuals drawn from multiple families. These families had also intermarried over time to ensure political power remained among their relatives. This tradition gave way during the empire’s twilight when the families welcomed local community leaders as well in a bid to retain power.
Since its first application to unravel the genome sequence of a single Neandertal individual, researchers have used palaeogenomics for population-scale studies with great success — so much so that it stands today to help historiography, anthropology, and sociology make big advances as well.
The authors are senior consultants at Vishwanath Cancer Care Foundation and adjunct professors at IIT Kanpur and Dr. D.Y. Patil Medical College, Hospital & Research Centre, Pune.
