some archaeologists, PIE speakers cannot be assumed to have been a single, identifiable people or tribe, but were a group of loosely related populations ancestral to the later, still partially prehistoric, Bronze Age Indo-Europeans. This view is held especially by those archaeologists who posit an original homeland of vast extent and immense time depth. However, this view is not shared by linguists, as proto-languages, like all languages before modern transport and communication, occupied small geographical areas over a limited time span, and were spoken by a set of close-knit communities—a tribe in the broad sense. Researchers have put forward a great variety of proposed locations for the first speakers of Proto-Indo-European. Few of these hypotheses have survived scrutiny by academic specialists in Indo-European studies sufficiently well to be included in modern academic debate. Pontic-Caspian steppe hypothesis The Kurgan (or Steppe) hypothesis was first formulated by Otto Schrader (1883) and V. Gordon Childe (1926), and was later systematized by Marija Gimbutas from 1956 onwards. The name originates from the kurgans (burial mounds) of the Eurasian steppes. The hypothesis suggests that the Indo-Europeans, a patriarchal, patrilinear, and nomadic culture of the Pontic–Caspian steppe (now part of Eastern Ukraine and Southern Russia), expanded in several waves during the 3rd millennium BC, coinciding with the taming of the horse. Leaving archaeological signs of their presence (see Corded Ware culture), they subjugated the supposedly peaceful, egalitarian and matrilinear European neolithic farmers of Gimbutas' Old Europe. A modified form of this theory by J. P. Mallory, dating the migrations earlier (to around 3500 BC) and putting less insistence on their violent or quasi-military nature, remains the most widely accepted view of the Proto-Indo-European expansion. Armenian highland hypothesis The Armenian hypothesis, based on the glottalic theory, suggests that the Proto-Indo-European language was spoken during the 4th millennium BC in the Armenian Highland. This Indo-Hittite model does not include the Anatolian languages in its scenario. The phonological peculiarities of PIE proposed in the glottalic theory would be best preserved in the Armenian language and the Germanic languages, the former assuming the role of the dialect which remained in situ, implied to be particularly archaic in spite of its late attestation. Proto-Greek would be practically equivalent to Mycenean Greek and would date to the 17th century BC, closely associating Greek migration to Greece with the Indo-Aryan migration to India at about the same time (viz., Indo-European expansion at the