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. 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 since 2015. 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), 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) Domesticated cattle