Kurgan hypothesis

The Kurgan hypothesis (also known as the Kurgan theory or Kurgan model) or Steppe theory is the most widely accepted proposal to identify the Proto-Indo-European homeland from which the Indo-European languages spread out throughout Europe and parts of Asia. 
It postulates that the people of a Kurgan culture in the Pontic steppe north of the Black Sea were the most likely speakers of the Proto-Indo-European language (PIE). The term is derived from the Russian "kurgan" (), meaning tumulus or burial mound.
The Steppe theory was first formulated by Otto Schrader (1883) and V. Gordon Childe (1926), then systematized in the 1950s by Marija Gimbutas, who used the term to group various cultures, including the Yamnaya (or Pit Grave), culture and its predecessors. David Anthony instead uses the core Yamnaya culture and its relationship with other cultures as a point of reference.
Gimbutas defined the Kurgan culture as composed of four successive periods, with the earliest (Kurgan I) including the Samara and Seroglazovo cultures of the Dnieper–Volga region in the Copper Age (early 4th millennium BC). The people of these cultures were nomadic pastoralists, who, according to the model, by the early 3rd millennium BC had expanded throughout the Pontic–Caspian steppe and into Eastern Europe.
Three genetic studies in 2015 gave partial support to Gimbutas's Kurgan theory regarding the Indo-European Urheimat. According to those studies, haplogroups R1b and R1a, now the most common in Europe (R1a is also common in South Asia) would have expanded from the steppes north of the Pontic and Caspian seas, along with the Indo-European languages; they also detected an autosomal component present in modern Europeans which was not present in Neolithic Europeans, which would have been introduced with paternal lineages R1b and R1a, as well as Indo-European languages.
History.
Predecessors.
Arguments for the identification of the Proto-Indo-Europeans as steppe nomads from the Pontic–Caspian region had already been made in the 19th century by German scholars Theodor Benfey (1869) and (1870), followed notably by Otto Schrader (1883, 1890). Theodor Poesche had proposed the nearby Pinsk Marshes. In his standard work about PIE and to a greater extent in a later abbreviated version, Karl Brugmann took the view that the urheimat could not be identified exactly at that time, but he tended toward Schrader's view. However, after Karl Penka's 1883 rejection of non-European origins, most scholars favoured a Northern European origin (see North European hypothesis).
The view of a Pontic origin was still strongly favoured, e.g., by the archaeologists V. Gordon Childe and Ernst Wahle. One of Wahle's students was Jonas Puzinas, who in turn was one of Gimbutas's teachers. Gimbutas, who acknowledges Schrader as a precursor, was able to marshal a wealth of archaeological evidence from the territory of the Soviet Union (and other countries then belonging to the eastern bloc) not readily available to scholars from western countries, enabling her to achieve a fuller picture of prehistoric Europe.
Overview.
When it was first proposed in 1956, in "The Prehistory of Eastern Europe, Part 1", Marija Gimbutas's contribution to the search for Indo-European origins was an interdisciplinary synthesis of archaeology and linguistics. The Kurgan model of Indo-European origins identifies the Pontic–Caspian steppe as the Proto-Indo-European (PIE) urheimat, and a variety of late PIE dialects are assumed to have been spoken across the region. According to this model, the Kurgan culture gradually expanded until it encompassed the entire Pontic–Caspian steppe, Kurgan IV being identified with the Yamnaya culture of around 3000 BC.
The mobility of the Kurgan culture facilitated its expansion over the entire region, and is attributed to the domestication of the horse and later the use of early chariots. The first strong archaeological evidence for the domestication of the horse comes from the Sredny Stog culture north of the Azov Sea in Ukraine, and would correspond to an early PIE or pre-PIE nucleus of the 5th millennium BC. Subsequent expansion beyond the steppes led to hybrid, or in Gimbutas's terms "kurganized" cultures, such as the Globular Amphora culture to the west. From these kurganized cultures came the immigration of Proto-Greeks to the Balkans and the nomadic Indo-Iranian cultures to the east around 2500 BC.
Kurgan culture.
Cultural horizon.
Gimbutas defined and introduced the term "Kurgan culture" in 1956 with the intention of introducing a "broader term" that would combine Sredny Stog II, Pit Grave, and Corded ware horizons (spanning the 4th to 3rd millennia in much of Eastern and Northern Europe). The model of a "Kurgan culture" brings together the various cultures of the Copper Age to Early Bronze Age (5th to 3rd millennia BC) Pontic–Caspian steppe to justify their identification as a single archaeological culture or cultural horizon, based on similarities among them. The eponymous construction of kurgans (mound graves) is only one among several factors. As always in the grouping of archaeological cultures, the dividing line between one culture and the next cannot be drawn with hard precision and will be open to debate.
Cultures that Gimbutas considered as part of the "Kurgan culture":
Stages of culture and expansion.
Gimbutas's original suggestion identifies four successive stages of the Kurgan culture:
In other publications she proposes three successive "waves" of expansion:
Further expansion during the Bronze Age.
The Kurgan hypothesis describes the initial spread of Proto-Indo-European during the 5th and 4th millennia BC. As used by Gimbutas, the term "kurganized" implied that the culture could have been spread by no more than small bands who imposed themselves on local people as an elite. This idea of the PIE language and its daughter-languages diffusing east and west without mass movement proved popular with archaeologists in the 1970s (the "pots-not-people" paradigm). The question of further Indo-Europeanization of Central and Western Europe, Central Asia and Northern India during the Bronze Age is beyond its scope, far more uncertain than the events of the Copper Age, and subject to some controversy. The rapidly developing field of archaeogenetics and genetic genealogy since the late 1990s has not only confirmed a migratory pattern out of the Pontic Steppe at the relevant time, it also suggests the possibility that the population movement involved was more substantial than anticipated and invasive.
Revisions.
Invasion versus diffusion scenarios (1980s onward).
Gimbutas believed that the expansions of the Kurgan culture were a series of essentially hostile military incursions where a new warrior culture imposed itself on the peaceful, matrilinear, and matrifocal (but not matriarchal) cultures of "Old Europe", replacing it with a patriarchal warrior society, a process visible in the appearance of fortified settlements and hillforts and the graves of warrior-chieftains:
The process of Indo-Europeanization was a cultural, not a physical, transformation. It must be understood as a military victory in terms of successfully imposing a new administrative system, language, and religion upon the indigenous groups.
In her later life, Gimbutas increasingly emphasized the authoritarian nature of this transition from the egalitarian process of the nature/earth mother goddess (Gaia) to a patriarchal society and the worship of the father/sun/weather god (Zeus, Dyaus).
J. P. Mallory (in 1989) accepted the Kurgan hypothesis as the "de facto" standard theory of Indo-European origins, but he recognized criticism of any alleged, but not actually stated, "radical" scenario of military invasion; the slow accumulation of influence through coercion or extortion – Gimbutas's actual main scenario – was often taken as general and immediate raiding and then conquest:
Alignment with Anatolian hypothesis (2000s).
Alberto Piazza and Luigi Luca Cavalli-Sforza have tried in the 2000s to align the Anatolian hypothesis with the steppe theory. According to Alberto Piazza, writing in 2000, "[i]t is clear that, genetically speaking, peoples of the Kurgan steppe descended at least in part from people of the Middle Eastern Neolithic who immigrated there from Turkey." According to Piazza and Cavalli-Sforza (2006), the Yamna-culture may have been derived from Middle Eastern Neolithic farmers who migrated to the Pontic steppe and developed pastoral nomadism. Wells agrees with Cavalli-Sforza that there is ""some" genetic evidence for migration from the Middle East." Nevertheless, the Anatolian hypothesis is incompatible with the linguistic evidence.
Anthony's revised steppe theory (2007).
David Anthony's "The Horse, the Wheel and Language" describes his "revised steppe theory". David Anthony considers the term "Kurgan culture" so lacking in precision as to be useless, instead using the core Yamnaya culture and its relationship with other cultures as a point of reference. He points out that 
He does not include the Maykop culture among those that he considers to be IE-speaking, presuming instead that they spoke a Caucasian language.
See also.
Genetics
Competing hypotheses