The Oxus civilization expanded as far east as western edge of the Indus Valley during the period between 2200 and 1800 B.C. These people, who were the ancestors of the Indo-Aryans, used the term "Aryan" to identify their ethnicity, culture, and religion. Scholars know this when they read the ancient texts of these people; the Avesta of Iranian people and the Vedas of Indo-Aryans.