Black banners from the east: The establishment of the 'Abbasid state-incubation of a revolt

The battle on the Ziib was lost in the late afternoon Sunday, January 25. 750. To no avail. Caliph Marwan, the last Umayyad caliph. endeavored to rally round him his shattered army that was trapped between the deep ravine of the Zab and the spears of the black clad Easterners led by 'Abdallah ibn 'Ali. In the heat of battle. earlier in the day. they had dismounted from their horses as a sign of their determination to fight to the death. and now they drove hard into the caliph's crushed lines. black banners hoisted over the black human phalanxes.