Archaeological Evidence of the Rise of the Dari Persian Language in Khorasan

At the time of the invasion of Iran by the Arabs, the Dari Persian language flourished in the Greater Khorasan region. During the first two decades of the Arab invasion, Dari Persian, which was the Sasanian court language, expanded geographically due to the displacement of populations from the Ctesiphon and Fars regions and the flight of the king and large court families to the eastern regions, especially Khorasan. A major unanswered question concerns how the Persian language spread in Khorasan in relation to the process of population movement of Iranians from the west and south to the eastern regions of the collapsed Sasanian polity. In this study, by examining the transition period from the Sasanian to the beginning of the Islamic era, especially regarding fire temples that lasted until the early centuries of the Islamic era, we conclude that with the statistical fluctuation of the number of sites in these periods, it seems that Iranians were under attack. Early hardships in front of the swordsmen with the courtiers from the southern regions of Iran, especially Fars and their imperial center, Ctesiphon, went to the land of Ādur-Burzēn-Mihr, i.e., Khorasan. These immigrants adopted two methods of settlement: first, in the villages, and second, by moving through an area as nomads. This population was able to survive with this system that was formed at the end of the Sasanian period. One of the compromises that supported the endurance of this system was the protection of Persian culture and language in Khorasan, where much progress was made.