The Geographical Dictionary of Ancient and Mediaeval India c5.s1.91

c5.s1.91

Ariana—That portion of Central Asia (mentioned by Strabo) which was the original abode of the Aryan race and which is called Airyan-vejo (Ārya-vija) in the Avesta. From its description as a very cold country and its situation on the north of India as it appears from the Vedas, it is considered to have been situated to the west of Bolurtagh and Mustagh (or Snowy Mountain) and near the source of the Amu and Syhun, including the Pamir. Sections of the Aryan race migrated to the west and settled themselves in Europe at different periods. Those that remained behind migrated subsequently to the south and settled themselves in Iran and the Punjab. Differences of opinion about agricultural and religious reforms, especially the introduction of the worship of Indra as a principal god to the lowering of Varuna, who always held the highest position in the hierarchy of the gods even from the time when they all resided in Central Asia, split up the early Aryan settlers of the Punjab into two parties, and led to the dissension which brought about a permanent separation between them. The party which opposed this innovation migrated to the north-west, and after residing for some time at Balkh and other places, finally settled themselves in Iran: they were the followers of Zarathustra and were called Zoroastrians, the ancestors of the modern Parsis. The other party, the ancestors of the Hindus, gradually spread their dominion from the Punjab and the bank of the Sarasvati to the east and south by their conquest of the aboriginal races (Max Müller's Science of Language).