Arya derives from Proto-Indo-Iranian steppe pastoralists of Andronovo and Sintashta cultures. Iranians distinguished from Indo-Aryans and steppe nomads by sedentarization in Greater Iran. Avesta marks Arya expanse in eastern Greater Iran, centered on Afghanistan-Tajikistan. Arya contrasts sharply with enemies Turyas, Sairimas, Dahas, Sainus north of Oxus River. Mythical king Thraetaona divides world: Tur (Turya) north-east, Sarm (Sairima) west, Iraj (Arya) south. Avestan stories depict Arya-Turya wars over Khvarenah, ending at Oxus border shot by Erekhsha. Kavi Xosrau kills Turanian king Franrasyan with all Aryas. Achaemenid kings Darius and Xerxes claim Arya lineage beyond Persian tribe. Old Persian calls language Arya – Ahura Mazda is Aryas' god. Herodotus names ancient Medes as Arioi (Aryas). Sassanians use Eran Shahr as Aryas' dominion tied to Zoroastrianism. Arya fades post-Islam due to Zoroastrian ties, revives as Eran toponym. Modern Iranian derives from Eran, back-formed from Arya. Reza Shah renames Persia to Iran, uses Aryamehr title.