Kurgan hypothesis in the context of "Pre-Roman Iron Age"

The Indo-European migrations are hypothesized migrations of peoples who spoke Proto-Indo-European (PIE) and the derived Indo-European languages, which took place from around 4000 to 1000 BCE, potentially explaining how these related languages came to be spoken across a large area of Eurasia, spanning from the Indian subcontinent and Iranian plateau to Atlantic Europe.

While these early languages and their speakers are prehistoric (lacking documentary evidence), a synthesis of linguistics, archaeology, anthropology and genetics has established the existence of Proto-Indo-European and the spread of its daughter dialects through migrations of large populations of its speakers, as well as the recruitment of new speakers through emulation of conquering elites. Comparative linguistics describes the similarities between various languages governed by laws of systematic change, which allow the reconstruction of ancestral speech (see Indo-European studies). Archaeology traces the spread of artifacts, habitations, and burial sites presumed to be created by speakers of Proto-Indo-European in several stages, from their hypothesized Proto-Indo-European homeland to their diaspora throughout Western Europe, Central Asian, and South Asia, with incursions into East Asia. Recent genetic research, including paleogenetics, has increasingly delineated the kinship groups involved in this movement.

Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. No direct record of Proto-Indo-European has been discovered; its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. Far more work has gone into reconstructing PIE than any other proto-language, and it is the best understood of all proto-languages of its age. The majority of linguistic work during the 19th century was devoted to the reconstruction of PIE and its daughter languages, and many of the modern techniques of linguistic reconstruction (such as the comparative method) were developed as a result.

PIE is hypothesized to have been spoken as a single language from approximately 4500 BCE to 2500 BCE during the Late Neolithic to Early Bronze Age, though estimates vary by more than a thousand years. According to the prevailing Kurgan hypothesis, the original homeland of the Proto-Indo-Europeans may have been in the Pontic–Caspian steppe of eastern Europe. The linguistic reconstruction of PIE has provided insight into the pastoral culture and patriarchal religion of its speakers. As speakers of Proto-Indo-European became isolated from each other through the Indo-European migrations, the regional dialects of Proto-Indo-European spoken by the various groups diverged, as each dialect underwent shifts in pronunciation (the Indo-European sound laws), morphology, and vocabulary. Over many centuries, these dialects transformed into the known ancient Indo-European languages. From there, further linguistic divergence led to the evolution of their current descendants, the modern Indo-European languages.

In archaeogenetics, the term Western Steppe Herders (WSH), or Western Steppe Pastoralists, is the name given to a distinct ancestral component first identified in individuals from the Chalcolithic steppe around the start of the 5th millennium BC, subsequently detected in several genetically similar or directly related ancient populations including the Khvalynsk, Repin, Sredny Stog, and Yamnaya cultures, and found in substantial levels in contemporary populations of Europe, Central Asia, South Asia and West Asia. This ancestry is often referred to as Yamnaya ancestry, Yamnaya-related ancestry, Steppe ancestry or Steppe-related ancestry.

Western Steppe Herders are considered to be descended from a merger between Eastern Hunter-Gatherers (EHGs) and Caucasus Hunter-Gatherers (CHGs). The WSH component is modeled as an admixture of EHG and CHG ancestral components in roughly equal proportions, with the majority of the Y-DNA haplogroup contribution from EHG males. The Y-DNA haplogroups of Western Steppe Herder males are not uniform, with the Yamnaya culture individuals mainly belonging to R1b-Z2103 with a minority of I2a2, the earlier Khvalynsk culture also with mainly R1b but also some R1a, Q1a, J, and I2a2, and the later, high WSH ancestry Corded Ware culture individuals mainly belonging to haplogroup R1b in the earliest samples, with R1a-M417 becoming predominant over time.

The Yamnaya (/ˈjæmnaɪə/ YAM-ny-ə) or Yamna culture (/ˈjæmnə/ YAM-nə), also known as the Pit Grave culture or Ochre Grave culture, is a late Copper Age to early Bronze Age archaeological culture of the region between the Southern Bug, Dniester, and Ural rivers (the Pontic–Caspian steppe), dating to 3300–2600 BC. It was discovered by Vasily Gorodtsov following his archaeological excavations near the Donets River in 1901–1903. Its name derives from its characteristic burial tradition: yámnaya (я́мная) is a Russian adjective that means 'related to pits' (я́ма, yáma), as these people buried their dead in tumuli (kurgans) containing simple pit chambers. Research in recent years has found that Mykhailivka, on the lower Dnieper River, Ukraine, formed the core Yamnaya culture (c. 3600–3400 BC).

The Yamnaya culture is of particular interest to archaeologists and linguists, as the widely accepted Kurgan hypothesis posits that the people who produced the Yamnaya culture spoke a stage of the Proto-Indo-European language. The speakers of the Proto-Indo-European (PIE) language embarked on the Indo-European migrations that gave rise to the widely dispersed Indo-European languages of today.

Indo-European studies (German: Indogermanistik) is an interdisciplinary field that examines the Indo-European languages and related cultural history through historical linguistics, comparative philology, archaeology, and genetics.

The discipline coalesced in late eighteenth- and nineteenth-century Europe as comparative linguists including Marcus Zuerius van Boxhorn, Franz Bopp, and August Schleicher refined methods for reconstructing a shared ancestry among the languages. Research centers on rebuilding the Proto-Indo-European language, homeland, and society by combining comparative analysis with archaeological, mythological, and genetic evidence to test models such as the Kurgan hypothesis. Dedicated programs, research centers, journals, and book series sustain Indo-European studies across Europe and North America.