of years before the estimated arrival of PIE. The first farmers lacked, and PIE speakers possessed, innovations like ploughs, wheels, and domesticated horses. PIE is strikingly deficient in words for the crops that defined the first farmers. Hittite, the oldest known Indo-European language of Turkey, is not the Indo-European language closest to pure PIE, as one might expect from Renfrew's Turkey-based theory, but is instead the most deviant language and the one least Indo-European in its vocabulary. Renfrew's theory rests on nothing more than a syllogism: farming probably caused a steamroller, the PIE steamroller requires a cause, so farming is assumed to have been that cause. Everything else suggests that farming instead brought to Europe the older languages that PIE overran, like Etruscan and Basque.
Yet around 5000–3000 BC—at the right time for PIE origins—there was a second economic revolution in Eurasia. This later revolution coincided with the beginnings of metallurgy and involved a greatly expanded use of domestic animals—not just for meat and hides, as humans had been using wild animals for a million years, but for new purposes that included milk, wool, pulling ploughs, pulling wheeled vehicles, and riding. The revolution is richly reflected in the PIE vocabulary, through words for 'yoke' and 'plough', 'milk' and 'butter', 'wool' and 'weave', and a host of words associated with wheeled vehicles ('wheel', 'axle', 'shaft', 'harness', 'hub', and 'lynch-pin'). The economic significance of this revolution was to increase human population and power far beyond the levels made possible by farming and herding alone. For instance, through milk and its products one cow gradually yielded many more calories than did its meat alone. Ploughing allowed a farmer to plant much more acreage than he could with a hoe or digging stick. Animal-drawn vehicles allowed people to exploit far more land and still bring its produce to their village for processing.
For some of these advances it is hard to say where they arose, because they spread so quickly. For example, wheeled vehicles are unknown before 3300 BC, but within a few centuries of that date they are widely recorded throughout Europe and the Middle East. But there is one crucial advance whose origin can be identified: the domestication of horses. Just before their domestication, wild horses were absent from the Mideast and southern Europe, rare in northern Europe, and abundant only in the steppes of Russia eastwards. The first evidence of horse domestication is for the Sredny Stog culture around 4000 BC, in the steppes just north of the Black Sea, where archaeologist David Anthony has identified wear-marks on horses' teeth that indicate use of a bit for riding.
Throughout the world, wherever and whenever domestic horses have been introduced, they have yielded enormous benefits for human societies (Chapter Fourteen). For the first time in human evolution, people could travel overland faster than their own legs could propel them. Speed helped hunters run down their prey and helped herders manage their sheep and cattle over large areas. Most importantly, speed helped warriors to launch quick surprise raids on distant enemies and to withdraw again before the enemies had time to organize a counterattack. Throughout the world the horse revolutionized warfare and enabled horse-owning peoples to terrorize their neighbours. The stereotype that Americans hold of Great Plains Indians as fearsome mounted warriors was actually created only recently, within a few generations from 1660 to 1770. Since European horses reached the US West in advance of Europeans themselves and other European goods, we can be sure that the horse alone was what transformed Plains Indian society.
The inferred homeland where proto-Indo-European (PIE), the mother tongue, was spoken lay in the Russian steppes north of the Black Sea and east of the Dnieper River.
Archaeological evidence makes clear that domestic horses had similarly transformed human society on the Russian steppe much earlier, around 4000 BC. The steppe habitat of open grassland was hard for people to exploit until they could use horses to solve the problems of distance and transport. Human occupation of the Russian steppe accelerated with horse domestication and then exploded with the invention of ox-drawn wheeled vehicles around 3300 BC. The steppe economy came to be based on the combination of sheep and cattle for meat, milk, and wool, plus horses and wheeled vehicles for transport, and supplemented by a little farming.
There is no evidence for intensive agriculture and food storage at those early steppe sites, in marked contrast to the abundant evidence at other European and Mideast sites around the same time. Steppe people lacked large permanent settlements and were evidently highly mobile—again in contrast to the villages with rows of hundreds of two-storey houses in southeast Europe at the time. What the horsemen lacked in architecture, they made up for in military zeal, as attested by their lavish tombs (for men only!), filled with enormous numbers of daggers and other weapons, and sometimes even with wagons and horse skeletons.
Thus, Russia's Dnieper River (see map on page 243) marked an abrupt cultural boundary:, to the east, the well-armed horsemen, to the west, the rich farming villages with their granaries. That proximity of wolves and sheep spelt T-R-O-U-B-L-E. Once the invention of the wheel completed the horsemens' economic package, their artifacts indicate a very rapid spread for thousands of miles eastwards through the steppes of central Asia (see map). From that movement, the ancestors of the Tocharians may have arisen. The steppe peoples' spread westwards is marked by the concentration of European farming villages nearest the steppes into huge defensive settlements, then the collapse of those societies, and the appearance of characteristic steppe graves in Europe as far west as Hungary.
Of the innovations that drove the steppe peoples' steamroller, the sole one for which they clearly get full credit is the domestication of the horse. They might also have developed wheeled vehicles, milking, and wool technology independently of the Mideast's civilizations, but they borrowed sheep, cattle, metallurgy, and probably the plough from the Mideast or Europe. Thus, there was no single 'secret weapon' that alone explains the steppe expansion. Instead, with horse domestication the steppe peoples became the first to put together the economic and military package that came to dominate the world for the next 5,000 years—especially after they added intensive agriculture upon invading southeastern-Europe. Hence their success, like that of the second-stage European expansion that began in 1492, was an accident of bio-geography. They happened to be the peoples whose homeland combined abundant wild horses and open steppe with proximity to Mideastern and European centres of civilization.
As archaeologist Marija Gimbutas, from the University of California, Los Angeles, has argued, the Russian steppe peoples who lived west of the Ural Mountains in the fourth millenium BC fit quite well into our postulated picture of proto-Indo-Europeans. They lived at the right time. Their culture included the important economic elements reconstructed for PIE (like wheels and horses), and lacked the elements lacking from PIE (like battle chariots and many crop terms). They lived in the right place for PIE: the temperate zone, south of Finno-Ugric peoples, near the later homeland of Lithuanians and other Baits.
If the fit is so good, why does the steppe theory of Indo-European origins remain so controversial? There would have been no controversy if archaeologists had been able to demonstrate a rapid expansion of steppe culture from southern Russia all the way to Ireland around 3000 BC. But that did not happen; direct evidence of the steppe invaders themselves extends no further west than Hungary. Instead, around and after 3000 BC, one finds a bewildering array of other cultures developing in Europe and named for their artifacts (for instance, the 'Corded Ware and Battle-axe Culture'). Those emerging Western European cultures combine steppe elements like horses and militarism with old Western European elements, especially settled agriculture. Such facts cause many archaeologists to discount the steppe hypothesis altogether, and to see the emerging Western European cultures as local developments.
However, there is an obvious reason why the steppe culture could not spread intact to Ireland. The steppe itself reaches its western limit in the plains of Hungary. That is where all subsequent steppe invaders of Europe, such as the Mongols, stopped. To spread further, steppe society had to adapt to the forested landscape of Western Europe—by adopting intensive agriculture, or by taking over existing European societies and hybridizing with their peoples. Most of the genes of the resulting hybrid societies may have been the genes of Old Europe.
If steppe people imposed PIE, their mother tongue, on southeastern Europe as far as Hungary, then it was the resulting daughter Indo-European culture, not the original steppe culture itself, that spread to derived granddaughter cultures elsewhere in Europe. Archaeological evidence of major cultural change suggests that such granddaughter cultures may have arisen throughout Europe and east to India between WOO and 1500 BC. Many non-Indo-European languages held out long enough to be preserved in writing (like Etruscan), and Basque still
