Facing Facts, even fraught ones: the quest for proto-Indo-Europeans in 2023
How genetics illuminates the rise of Eurasian steppe pastoralism
Today, over three billion humans distributed across every continent claim Indo-European languages as their mother tongue. This status is the outcome of myriad documented historical events, and an even greater mass of shadowy circumstances we can only intuit, which thousands of years ago catapulted an obscure tribe of Eurasians into position as the direct genetic ancestors of hundreds of millions of people alive today, not to mention the cultural pathbreakers to billions more. The rise and spread of the British Empire and Spain’s New World conquest were two key phenomena instrumental to the vast historical spread of the Indo-European languages, English and Spanish. But Indo-European languages were already widespread long before the modern rise of Western imperialism.
Before Rome, before Greece, even before Sumer, five millennia ago, Indo-Europeans were sowing their genes and memes across Eurasia’s width and breadth. By 3300 BC, warlike nomads from the Pontic steppe north of the Black Sea had exploded out of their homeland, pounding east to Mongolia’s Altai mountains. Five hundred years later, their successors shot in the opposite direction, reaching Denmark and the North Sea, and circling the Baltic from north to south. For thousands of years, Indo-Europeans expanded to new domains under cover of unlettered darkness; unrecorded and dimly recalled. Europe’s first decipherable writing, Linear B dates to 1400 BC in Greece. But by then, on the edge of prehistory, Indo-European languages had long since spread across the Mediterranean’s whole northern shore, sweeping Iberia and the Italian peninsula in the west, and thrusting far to the southeast, all the way to India’s Gangetic plain, 5,000 miles as the crow flies. While Old Kingdom Egypt built the massive pyramids and set in place the fundamentals of what it meant to be civilized for later cultures, primitive and illiterate nomads blasted their way beyond forbidding mountain ranges and trekked doggedly across rugged uplands, from the Pyrenees to the Pamirs. Through sheer force of numbers, this unstoppable people demographically flooded Eurasia’s ancient farming civilizations, everywhere from Britain to India.
The puzzle of the Indo-Europeans reflects the reality that Indo-European languages’ early spread occurred in darkness, far from any recorded texts’ illuminating light. There was no one to inscribe for posterity narratives and names, to make incarnate those fervid moments of conquest for us. Long after the rise and fall of civilizations, genuine history remains alive to us, indelibly inhabited by lively dramatis personae. But of course even absent writing, fragments of past realities persist into the present. The consistently shared lineaments of their received mythos, from Hindu scripture to Greek mythology, tell us Indo-European societies were patriarchal and dominated by powerful men who deftly directed the volatility and violence of young warriors outward, against enemies and allies alike. And yet we can name no lyrically depicted heroes from their age of conquest, not even the likes of the semi-historical Sumerian Gilgamesh or China’s Duke of Zhou. Nor can we summon the names of grand and epic cities, for the early Indo-Europeans built none. Their ancient temples were the vast open landscapes of the steppe itself, the abode of the sky god known to the Romans as Jupiter, the Greeks as Zeus Patēr and the Indian Aryans as Dyáuṣ Pitṛ́.
Until the development of computational phylogenetic tools in the 1990s, at best, inferences about the rise and spread of Indo-Europeans had to be pieced together from innumerable shards of pottery left scattered and inert by otherwise mute prehistoric ghosts. Painstakingly reconstructed back-projections of shared vocabularies cobbled together from modern and dead languages were our only other eloquent clues to ancestral linguistic, sociological and cultural histories; a too-secret past more conjectured than discovered. Though genomic technologies, which allow for the assay of hundreds, thousands and even millions of genetic markers at a time, were essential to unlock a motherlode of fresh data, the real inflection point was the synergy with the new field of ancient DNA after 2010. This fledgling discipline, also called paleogenomics, allowed for precise and quantitative measurements of human population dynamics through space and time, an accurate genealogy of the past orders of magnitude more informative than what we knew even of contemporary populations just decades earlier. Though we can never hope to invent a time machine to hear the languages those first nomadic herders on the Eurasian steppe spoke, we can with astonishing fidelity now trace the rise and spread of whole peoples and the flourishing or extinction of lost races. The archaeological and linguistic theories of the last two centuries of scholarship were generally, by definition, woefully short on data. Still, they were rich in hypotheses, and the population genomic framework of the 21st century can finally crown the worthiest contenders from that sample space of ingenious theories that had for so long remained at best-strained speculations.
We now know that there were mass migrations out of the steppe, whole folk movements where one people replaced another in totality on a scale unimagined a generation ago. The patriarchal mythology of the Indo-Europeans we inherited reflected the true patriarchal organization of their societies; ancient DNA documents the star-like expansion of singular male lineages across centuries and then their successive obliteration in the face of younger, more vigorous competitor lines. In places like Bronze Age Germany and Poland, paleogenomics can also attest to the assimilation of foreign women into villages dominated by a single male founder’s lineage. Isotope analysis of chemical profiles in bones that serve as a signature of local mineral content, record a wide distribution of birthplaces for the women. While the men in the villages shared the same Y chromosome, the women brought diverse mtDNA lineages, confirming the male-centered culture of these early migrating Indo-Europeans. In vast regions of Northern Europe, the Bronze Age steppe herders replaced earlier farming societies, the invaders unceremoniously sweeping away all before them, which often meant the extermination of indigenous male-dominated elites (ancient DNA studies show that Neolithic farmers too structured their societies around male kin-groups). However, there was some notable variation in the interaction between newcomers and older populations they conquered. Scandinavia and Britain retain almost no imprint of the Neolithic people, evidence of steppe merciless steppe pastoralist ferocity. In contrast, Greece and India’s invading nomads remained a substantial minority who reshaped the conquered people in their own image while being ineluctably altered by them, resulting in synthetic new cultures (the indigenous name for India, Bhārat, literally comes from an Aryan tribe).
Despite accumulating victory upon victory, the Indo-Europeans were not, crucially, civilization-bearers. Their pastoralist world flourished atop the smoldering ruins of worlds lost, cultures that left behind hulking rough-hewn stone monuments and the faint outlines of vast villages that were once the loci of sophisticated civilizations. The early Indo-Europeans were barbarians par excellence; their arrival ushered in an age of animal competition, kill or be killed. In places like Spain, Italy and Scandinavia whole paternal lineages disappear upon their arrival, wholly replaced by patrilines which still define the peninsulas today. Though they left their legacy in flesh, archaeologically the early Indo-Europeans are ghosts, their primary material legacy being graves. They emerged out of darkness, beyond the view of history, and they brought darkness to many lands they conquered, a process only finally reversed by civilization’s creeping spread. More than 1,000 years after Neolithic Europe and its grand megaliths fell to the barbarian nomads, the two traditions would fuse to set the stage for the eventual rise of Greece, Rome and the world of the Celts.
Revenge of the fringe
When David W. Anthony wrote The Horse, the Wheel, and Language fifteen years ago, debates more than a century old still plagued our understanding of Indo-Europeans and their origins. In his decades-long career Anthony, along with other scholars like J. P. Mallory, has extended the 20th-century model of their mutual mentor, the Lithuanian archaeologist Marija Gimbutas, who first argued that the Indo-European languages arrived in Europe 5,000 years ago through the vector of patriarchal, warlike steppe herders who left vast signature burial mounds, kurgans, constructed for their elite.
Earlier in the 20th century, scholars had broadly accepted something similar to Gimbutas’ steppe kurgan model, imagining bloody invasions of warriors bringing the Indo-European languages to Europe prior to Greece and Rome’s rise. But in the 1980s, the famed British archaeologist Colin Renfrew, supported by population geneticists like L. L. Cavalli-Sforza, and later, linguistic phylogeneticists like Simon Greenhill, argued for an alternative model less reliant on nomadic vigor and more on the inevitable and impersonal forces of demography. These theorists posited that the Indo-European languages’ spread was driven by the migration out of Anatolia of farmers as early as 10,000 years ago. Instead of bellicose mobile cattle drivers, Renfrew imagined that the mathematically deterministic demographic increase of farming societies pushed them northwestward in a vast human wavefront, an expansion announced by the banality of reproduction rather than the thundering hooves of horses and swarms of nomadic warriors.
But many scholars were skeptical of this new framework, no matter the eminence of its proponents and the sophistication of its models. Though Gimbutas, Anthony and Mallory were all trained as archaeologists, the strength of the steppe origin theory was its multidisciplinary scope, in particular, its concordance with historical linguistics (see Anthony’s book, or Mallory’s In Search of the Indo-Europeans). Indeed, our retrospective discovery, or recognition, of the Indo-Europeans begins with language, not material remains. In 1786, a British judge stationed in India, Sir Walter Jones, observed striking similarities in three antique languages with high cultural prestige at the time: Latin, Ancient Greek and Sanskrit. Later in the 19th century, philologists like the German-born Max Müller, who studied the structure, grammar and vocabulary of ancient languages, concluded from similarities across texts in these tongues that there was a common linguistic family bracketing the Bay of Bengal to the Bay of Biscay, from Western Europe to South Asia. Besides nearly every European language, with the exceptions of Basque, Hungarian, Turkish and the Baltic’s Finnic tongues, this family of languages also encompassed Farsi, Iran’s dominant language, the languages of fully three-quarters of Indians, as well as extinct dialects in Anatolia like Hittite, Luvian and Palawan, and the languages of otherwise forgotten steppe Iranians like the Scythians. Today, over a third of humanity speaks an Indo-European language, from Portuguese on Eurasia’s westernmost promontory to Sinhala, on the island of Sri Lanka, just beyond the Indian subcontinent.
The congruences between these languages are readily apparent in their core lexicons, even at first blush. Below are the numbers one to ten in eight Indo-European languages plus two non-Indo-European ones:
More sophisticated analyses using paleolinguistics look at a list of core words that reflect the daily concerns and knowledge of these ancient people. As noted above, the terms and ideas preserved in their mythologies suggest that the early Indo-Europeans were pastoral and patriarchal. The catalog of animals and plants known to the early Indo-Europeans: horses, wolves and bears, beech and apple trees, also reflect life in a colder, high latitude bioregion. The ecology of the western Eurasian Pontic steppe, between the Dnieper and Don rivers, fits that bill. However, the early Indo-Europeans expanded into exotic territory rapidly and early, creating neologisms distinctive to each subgroup. The Sanskrit for elephant is hasti, similar to the word for hand, hasta. Clearly, the first Sanskrit-speaking Indo-Aryans constructed a word on the fly for a novel creature they had met, the “animal with the hand.” In contrast, the Indo-European word for horse can consistently be seen to be shared: ásùwa in Hittite, áśva in Sanskrit, ašva in Lithuanian and eoh in Old English (from which we get horse), indicative of a more long-standing common origin dating to the Eurasian steppe, where horses were both native and plentiful.
Nevertheless, these analyses buttressing the idea of migrations out of the steppe fell out of fashion after the mid-20th century. Not, crucially, because they were systematically discarded based on evidence, but because they grew irredeemably stained by contemporary politics. Philology was highly concentrated in the German-speaking world; in addition to Müller, the list of Germans in the field includes Friedrich Nietzsche and Jacob Grimm. This led, in the decades before World War II, to the fatal confluence of the study of Indo-Europeans, German nationalism and eventually National Socialism. Between 1900 and 1930 the philologist and archaeologist Gustaf Kossinna hypothesized that the Corded Ware archaeological culture of early Bronze Age East-Central Europe was instrumental in the spread of Indo-European languages, and these ideas were taken up and popularized by the Nazis after he died in 1931. Because the Corded Ware Culture (CWC) flourished in Poland and Czechoslovakia, and Kossinna connected Indo-European theory with the rise of the Germans, Hitler’s annexation of these two nations was justified partly by the presumed proto-Germanic character of the CWC once indigenous to that region. Beyond Kossinna, the whole field of Indo-European studies was tainted by Nazism’s radioactivity and its repugnant social and political implications. Any model of prehistoric migration had to reckon with widespread scholarly suspicion about the concept after reflexive aversion from any thought favored by Hitler’s regime.