The Role of Iranians in the Capture of Iran by Arabs until the End of First Century A.H (groups, motives, kinds of cooperation)

Various theories have been brought up about the way of capturing Iran by Muslim Arabs and the fall of Sassanid Empire. The issue of how and why Arabs could deprive the great Sassanid Empire, and so they could dominate Iran in those times during almost one century is important, but the subject of the present study is the role of Iranians in the victory over Iran and their degree of cooperation with conquerors. Iranians cooperated with Arabs due to such motives as preserving properties, spirits and status, fearing and under compulsion. The Iranians ' cooperation with Arabs includes receiving news, reporting, receiving, military cooperation and so on. The era which is discussed in the present study begins with the first victories in the time of Abu- bakr, and continues until Yazdgerd death and the end of the first century A.H.