 
 <prompt> Wetin happun four years before the Battle of the Zab for 750? Given di previous question, write a context wey contain di answer. E fit be 1 - 20 sentences. Context: <response>: Around 746, Abu Muslim come assume leadership of the Hashimiyya for Khurasan. For 747, e successfully start open rebellion against Umayyad rule, wey dem carry out under di black flag. E soon gain control of Khurasan, chase out di Umayyad governor, Nasr ibn Sayyar, and send army go west. Kufa fall to di Hashimiyya for 749, di last Umayyad stronghold for Iraq, Wasit, dey under siege, and for November of di same year Abu al-Abbas dey recognize as di new caliph for di mosque for Kufa. At dis point Marwan mobilize im troops from Harran and move go Iraq. For January 750 di two forces meet for di Battle of the Zab, and di Umayyads lose. Damascus fall to di Abbasids for April, and for August, Marwan die for Egypt. 