When construction of
Stonehenge began
about 3000 B.C., Britain
was inhabited by
Neolithic farmers.
A millennium later,
when it was finished, the
Neolithic population
had been replaced
by descendants
of the Yamnaya—
perhaps because the
latter carried plague.alongside the human DNA, geneticists found
the DNA of an early form of Yersinia pestis—the
plague microbe that killed roughly half of all
Europeans in the 14th century.
Unlike that flea-borne Black Death, this early
variant had to be passed from person to per-
son. The steppe nomads apparently had lived
with the disease for centuries, perhaps build-
ing up immunity or resistance—much as the
Europeans who colonized the Americas carried
smallpox without succumbing to it wholesale.
And just as smallpox and other diseases ravaged
Native American populations, the plague, once
introduced by the first Yamnaya, might have
spread rapidly through crowded Neolithic vil-
lages. That could explain both their surprising
collapse and the rapid spread of Yamnaya DNA
from Russia to Britain.
“Plague epidemics cleared the way for the
Yamnaya expansion,” says Morten Allentoft, an
evolutionary biologist at the Natural History
Museum of Denmark, who helped identify the
ancient plague DNA.
But that theory has a major question: Evidence
of plague has only just recently been docu-
mented in ancient Neolithic skeletons, and so
far, no one has found anything like the plague
pits full of diseased skeletons left behind after
the Black Death. If a plague wiped out Europe’s
Neolithic farmers, it left little trace.
WHETHER OR NOT they brought plague, the
Yamnaya did bring domesticated horses and
a mobile lifestyle based on wagons into Stone
Age Europe. And in bringing innovative metal
weapons and tools, they may have helped nudge
Europe toward the Bronze Age.
That might not have been the Yamnaya’s most
significant contribution to Europe’s develop-
ment. Their arrival on the continent matches
the time linguists pinpoint as the initial spread
of Indo-European languages, a family of hun-
dreds that includes most languages spoken from
Ireland to Russia to the northern half of India.
All are thought to have evolved from a single
proto-Indo-European tongue, and the question
of where it was spoken and by whom has been
debated since the 19th century. According to one
theory, it was the Neolithic farmers from Anatolia
who brought it into Europe along with farming.
Another theory, proposed a century ago by a
German scholar named Gustaf Kossinna, held
that the proto-Indo-Europeans were an ancient
race of north Germans—the people who made
Corded Ware pots and axes. Kossinna thought
that the ethnicity of people in the past—their
biological identity, in effect—could be deduced
from the stuff they left behind.
“Sharply defined archaeological cultural
areas,” he wrote, “correspond unquestionably
with the areas of particular people or tribes.”
The north German tribe of proto-Indo-
Europeans, Kossinna argued, had moved
outward and dominated an area that stretched
most of the way to Moscow. Nazi propagandists
later used that as an intellectual justification
for the modern Aryan “master race” to invade
eastern Europe.
Partly as a result, for decades after World
War II the whole idea that ancient cultural
shifts might be explained by migrations fell
into ill repute in some archaeological circles.
Even today it makes some archaeologists112 NATIONAL GEOGRAPHIC