Proto-Indo-European society is the reconstructed culture of Proto-Indo-Europeans, the ancient speakers of the Proto-Indo-European language, ancestor of all modern Indo-European languages. Historical linguistics combined with archaeological and genetic evidence have provided the current basis for understanding the culture and its people. The most widely accepted theory suggests that the culture emerged on the Pontic–Caspian steppe after 5000 BCE, a period known as the Chalcolithic, where smelted copper and stone tools were in use simultaneously. Proto-Indo-European speakers are considered to have been semi-nomadic, but domestication of cattle, first for ritual sacrifice and later for consumption, dairy production, and cereal cultivation, emerged as the culture shifted from herding and hunter-gatherer behaviours to farming. The social hierarchy included an upper class of priests, warriors and tribe chiefs and a lower class of commoners and slaves; patrilineality and patriarchy characteristics have been well-established. Trade, bolstered by access to wheeled wagons, connected Proto-Indo-European culture to others with archaeological and linguistic evidence supporting relations with Proto-Uralic peoples, Uruk, and Old European cultures.
Scientific approaches Many of the modern ideas in this field involve the unsettled Indo-European homeland debate about the precise origins of the language itself. There are four main approaches researchers have employed in their attempts to study this culture:
Historical linguistics (especially comparative linguistics): interpretations based on the reconstruction and identification of words and formulae (those cited *thus on this page, with a preceding asterisk) which formed part of the vocabulary of the Proto-Indo-European language. These are reconstructed on the basis of sound laws and shared grammatical structures; the definitions hereunder given for the roots should be read as "connotations" (the concepts associated with a word that were inherited in the daughter languages), close to their original "denotation" (the exact meaning at the time of the Proto-Indo-European language). Comparative mythology: interpretations based on the comparison of Indo-European beliefs to identify shared themes and characteristics. While few divine names can be confidently reconstructed due to foreign influences and considerable evolutions in beliefs, scholars have been able to recover parts of the Proto-Indo-European mythology. Comparative folklore is often overlooked in Indo-European studies due to the difficulty of dating the origin of folk stories. Archaeology: interpretations based on archaeological evidence of a material culture. The Kurgan hypothesis, proposed by archeologists Marija Gimbutas (1956) and David W. Anthony (2007), is the most widely accepted theory on the Indo-European homeland, and postulates an origin in the Pontic-Caspian steppes during the Chalcolithic period. What follows are interpretations based upon this hypothesis. Archaeogenetics: interpretations based on the study of ancient DNA to understand the nature of ancient human migrations and "mating networks". In support for the Kurgan hypothesis, Yamnaya migrations have been linked to the spread of Indo-Europeans languages in several genetic studies published in recent years. In support of the Anatolian Hypothesis, a study named "Mapping the Origins and Expansion of the Indo-European Language Family" gained widespread media attention in 2012, but received scrutiny from historical linguists, who accused the study of abandoning the comparative method and of conflating language with genes. Nonetheless, "Mapping the Origins" has been cited by many since its publication, highlighting an interdisciplinary gap between linguistics and genetics. Chronology Archaeologist David W. Anthony and linguist Donald Ringe distinguish three different cultural stages in the evolution of the Proto-Indo-European language:
Early (4500–4000 BCE), the common ancestor of all attested Indo-European languages, before the Anatolian split (Cernavodă culture; 4000 BCE); associated with the early Khvalynsk culture, Classic, or "post-Anatolian" (4000–3500), the last common ancestor of the non-Anatolian languages, including Tocharian; associated with the late Khvalynsk and Repin cultures, Late (3500–2500), in its dialectal period due to the spread of the Yamnaya horizon over a large area.
Early Khvalynsk (4900–3900 BCE)
Domesticated cattle were introduced around 4700 BCE from the Danube valley to the Volga-Ural steppes where the Early Khvalynsk culture (4900–3900) had emerged, associated by Anthony with the Early Proto-Indo-European language. Cattle and sheep were more important in ritual sacrifices than in diet, suggesting that a new set of cults and rituals had spread eastward across the Pontic-Caspian steppes, with domesticated animals at the root of the Proto-Indo-European conception of the universe. Anthony attributes the first and progressive domestication of horses, from taming to actually working with the animal, to this period. Between 4500 and 4200, copper, exotic ornamental shells and polished stone maces were exchanged across the Pontic–Caspian steppes from Varna, in the eastern Balkans, to Khvalynsk, near the Volga river. Around 4500, a minority of richly decorated single graves, partly enriched by imported copper items, began to appear in the steppes, contrasting with the remaining outfitted graves.
The Anatolian distinctive sub-family may have emerged from a first wave of Indo-European migration into southeastern Europe around 4200–4000, coinciding with the Suvorovo–to–Cernavoda I migration, in the context of a progression of the Khvalynsk culture westwards towards the Danube area, from which had also emerged the Novodanilovka (4400–3800) and Late Sredny Stog (4000–3500) cultures.
Recent genetic studies have shown that males of the Khvalynsk culture belonged to the Western Steppe Herder (WSH) cluster, which is a mixture of Eastern Hunter-Gatherer (EHG) and Caucasus Hunter-Gatherer (CHG) ancestry. This admixture appears to have happened on the eastern Pontic–Caspian steppe starting around 5,000 BC.
Late Khvalynsk/Repin (3900–3300 BCE)
Steppe economies underwent a revolutionary change between 4200 and 3300 BCE, in a shift from a partial reliance on herding, when domesticated animals were probably used principally as a ritual currency for public sacrifices, to a later regular dietary dependence on cattle, and either sheep or goat meat and dairy products. The Late Khvalynsk and Repin cultures (3900–3300), associated with the classic (post-Anatolian) Proto-Indo-European language, showed the first traces of cereal cultivation after 4000, in the context of a slow and partial diffusion of farming from the western parts of the steppes to the east. Around 3700–3300, a second migration wave of proto-Tocharian speakers towards South Siberia led to the emergence of the Afanasievo culture (3300–2500).
The spoke-less wheeled wagon was introduced to the Pontic-Caspian steppe around 3500 from the neighbouring North Caucasian Maykop culture (3700–3000), with which Proto-Indo-Europeans traded wool and horses. Interactions with the hierarchical Maykop culture, itself influenced by the Mesopotamian Uruk culture, had notable social effects on the Proto-Indo-European way of life. Meanwhile, the Khvalynsk-influenced cultures that had emerged in the Danube-Donets region after the first migration gave way to the Cernavodă (4000–3200), Usatovo (3500–2500), Mikhaylovka (3600–3000) and Kemi Oba (3700–2200) cultures, from west to east respectively.
Yamnaya period (3300–2600 BCE)
The Yamnaya horizon, associated with the Late Proto-Indo-European language (following both the Anatolian and Tocharian splits), originated in the Don-Volga region before spreading westwards after 3300 BCE, establishing a cultural horizon founded on kurgan funerals that stretched over a vast steppic area between the Dnieper and Volga rivers. It was initially a herding-based society, with limited crop cultivation in the eastern part of the steppes, while the Dnieper-Donets region was more influenced by the agricultural Tripolye culture. Paleolinguistics likewise postulates Proto-Indo-European speakers as a semi-nomadic and pastoral population with subsidiary agriculture.
Bronze was introduced to the Pontic-Caspian steppes during this period. Following the Yamnaya expansion, long-distance trade in metals and other valuables, such as salt in the hinterlands, probably brought prestige and power to Proto-Indo-European societies. However, the native tradition of pottery making was weakly developed. The Yamnaya funeral sacrifice of wagons, carts, sheep, cattle, and horses was likely related to a cult of ancestors requiring specific rituals and prayers, a connection between language and cult that introduced the Late Proto-Indo-European language to new speakers. Yamnaya chiefdoms had institutionalized differences in prestige and power, and their society was organized along patron-client reciprocity, a mutual exchange of gifts and favors between their patrons, the gods, and human clients. The average life expectancy was fairly high, with many individuals living to 50–60 years old. The language itself appeared as a dialect continuum during this period, meaning that neighbouring dialects differed only slightly between each other, whereas distant language varieties were probably no longer mutually intelligible due to accumulated divergences over space and time.
As the steppe became dryer and colder between 3500 and 3000, herds needed to be moved more frequently in order to feed them sufficiently. Yamnaya distinctive identity was thus founded on mobile pastoralism, permitted by two earlier innovations: the introduction of the wheeled wagon and the domestication of the horse. Yamnaya herders likely watched over their cattle and raided on horseback, while they drove wagons for the bulk transport of water or food. Light-framework dwellings could be easily assembled and disassembled to be transported on pack animals.
Another climate change that occurred after around 3000 led to a more favourable environment allowing for grassland productivity. Yamnaya new pastoral economy then experienced a third wave of rapid demographic expansion, that time towards Central and Northern Europe. Migrations of Usatovo people towards southeastern Poland, crossing through the Old European Tripolye culture from around 3300 BCE, followed by Yamnaya migrations towards the Pannonian Basin between 3100 and 2800, are interpreted by some scholars as movements of pre-Italic, pre-Celtic and pre-Germanic speakers.
The Proto-Indo-European language probably ceased to be spoken after 2500 as its various dialects had already evolved into non-mutually intelligible languages that began to spread across most of western Eurasia during the third wave of Indo-European migrations (3300–1500). Indo-Iranian languages were introduced to Central Asia, present-day Iran, and South Asia after 2000 BCE.
Social structure Class structure It is generally agreed that Proto-Indo-European society was hierarchical, with some form of social ranking and various degrees of social status. It is unlikely, however, that they had a rigidly stratified structure, or castes such as are found in historical India. There was a general distinction between free persons and slaves, typically prisoners of war or debtors unable to repay a debt. The free part of society was composed of an elite class of priests, kings and warriors, along with the commoners, with each tribe following a chief () sponsoring feasts and ceremonies, and immortalized in praise poetry.