Islam's impact on border areas 

How some Medieval populations in border areas negotiated political, cultural and social changes brought about by Islam  

From the Heritage Daily: UC history research examines how border areas and frontiers of the past adapted to major political, cultural and social shifts, specifically in terms of the rise of Islam in Asia and the Middle East.

Afghanistan, Iran and the one-time Soviet Central Asian states were frontiers in flux as the Islamic Caliphate spread beyond the Arabian Peninsula in the seventh through 10th centuries.

As such, different groups, such as the new Arab ruling class, the native landed gentry and local farmers, jockeyed for power, position and economic advantage over an approximately 300-year period as the Sasanian Empire collapsed and the Caliphate took its place.
[More at http://www.heritagedaily.com/2013/01/uc-research-unveils-how-some-medieval-cultures-adapted-to-rise-of-islam/70463