 There were tribesmen of "Bakr bin Wael" and "Tamim(Thamim)" in Khuzestan and Fars prior to the arrival of the Arab Muslim Armies.Some of these Arab groups were sedentary while others were nomadic.Some fought on behalf of the Sassanid Empire (Taghleb, Eyad), while others (Lakhmid, Shayban, Bakr bin Wael) began struggling against the Sassanids.