Indo-Iranian peoples, also known as Indo-Iranic peoples by scholars, and sometimes as Arya or Aryans from their self-designation, were a group of Indo-European peoples who brought the Indo-Iranian languages, a major branch of the Indo-European language family, to major parts of Eurasia in the second part of the 3rd millennium BC. They eventually branched out into Iranian peoples and Indo-Aryan peoples, predominantly in the geographical subregion of Southern Asia. Nomenclature The term Aryan has long been used to denote the Indo-Iranians, because Arya is indeed the self-designation of the ancient speakers of the Indo-Iranian languages, specifically the Iranian and the Indo-Aryan peoples, collectively known as the Indo-Iranians. Despite this, some scholars use the term Indo-Iranian to refer to this group, though the term "Aryan" remains widely used by most scholars, such as Josef Wiesehofer, Will Durant, and Jaakko Häkkinen. Population geneticist Luigi Luca Cavalli-Sforza, in his 1994 book The History and Geography of Human Genes, also uses the term Aryan to describe the Indo-Iranians. History Origin The early Indo-Iranians are commonly identified with the descendants of the Proto-Indo-Europeans known as the Sintashta culture and the subsequent Andronovo culture within the broader Andronovo horizon, and their homeland with an area of the Eurasian steppe that borders the Ural River on the west, the Tian Shan on the east (where the Indo-Iranians took over the area occupied by the earlier Afanasevo culture), and Transoxiana and the Hindu Kush on the south. Based on its use by Indo-Aryans in Mitanni and Vedic India, its prior absence in the Near East and Harappan India, and its 19th–20th century BC attestation at the Andronovo site of Sintashta, Kuzmina (1994) argues that the chariot corroborates the identification of Andronovo as Indo-Iranian. dated a chariot burial at Krivoye Lake to about 2000 BC, and a Bactria-Margiana burial that also contains a foal has recently been found, indicating further links with the steppes. Historical linguists broadly estimate that a continuum of Indo-Iranian languages probably began to diverge by 2000 BC, if not earlier, preceding both the Vedic and Iranian cultures. The earliest recorded forms of these languages, Vedic Sanskrit and Gathic Avestan, are remarkably similar, descended from the common Proto-Indo-Iranian language. The origin and earliest relationship between the Nuristani languages and that of the Iranian and Indo-Aryan groups is not completely clear. Expansion First wave – Indo-Aryans Two-wave models of Indo-Iranian expansion have been proposed by Burrow (1973)