radiocarbon dates to a much higher degree of accuracy. And finally, before the 1970s, parts of Eastern Europe and Central Asia had been off limits to Western scholars, while non-Western archaeologists did not have access to publication in Western peer-reviewed journals. The pioneering work of Marija Gimbutas, assisted by Colin Renfrew, at least partly addressed this problem by organizing expeditions and arranging for more academic collaboration between Western and non-Western scholars. The Kurgan hypothesis, the most widely held theory, depends on linguistic and archaeological evidence, but is not universally accepted. It suggests PIE origin in the Pontic–Caspian steppe during the Chalcolithic. A minority of scholars prefer the Anatolian hypothesis, suggesting an origin in Anatolia during the Neolithic. Other theories (Armenian hypothesis, Out of India theory, Paleolithic continuity theory, Balkan hypothesis) have only marginal scholarly support. In regard to terminology, in the 19th and early 20th centuries, the term Aryan was used to refer to the Proto-Indo-Europeans and their descendants. However, Aryan more properly applies to the Indo-Iranians, the Indo-European branch that settled parts of the Middle East and South Asia, as only Indic and Iranian languages explicitly affirm the term as a self-designation referring to the entirety of their people, whereas the same Proto-Indo-European root (*aryo-) is the basis for Greek and Germanic word forms which seem only to denote the ruling elite of Proto-Indo-European (PIE) society. In fact, the most accessible evidence available confirms only the existence of a common, but vague, socio-cultural designation of "nobility" associated with PIE society, such that Greek socio-cultural lexicon and Germanic proper names derived from this root remain insufficient to determine whether the concept was limited to the designation of an exclusive, socio-political elite, or whether it could possibly have been applied in the most inclusive sense to an inherent and ancestral "noble" quality which allegedly characterized all ethnic members of PIE society. Only the latter could have served as a true and universal self-designation for the Proto-Indo-European people. By the early twentieth century, this term had come to be widely used in a racist context referring to a hypothesized white, blonde and blue-eyed "master race" (Herrenrasse), culminating with the pogroms of the Nazis in Europe. Subsequently, the term Aryan as a general term for Indo-Europeans has been largely abandoned by scholars (though the term Indo-Aryan is still used to refer to the branch that settled in Southern Asia). Urheimat hypotheses According to