Hishām ibn ʿAbd al-Malik (reigned 724–743) was able to stem the tide temporarily. As the empire was reaching the limits of expansion—the Muslim advance into France was decisively halted at Poitiers (732), and Arab forces in Anatolia were destroyed (740)—frontier defenses, manned by Syrian troops, were organized to meet the challenge of Turks in Central Asia and Berbers (Imazighen) in North Africa. But in the years following Hishām’s death, feuds between the Qays and the Kalb erupted into major revolts in Syria, Iraq, and Khorāsān (745–746), while the mawālī became involved with the Hāshimiyyah, a religio-political faction that denied the legitimacy of Umayyad rule. In 749 the Hāshimiyyah, aided by the western provinces, proclaimed as caliph Abū al-ʿAbbās al-Saffāḥ, who thereby became first of the ʿAbbāsid dynasty (Source: Britanica).
Abd Al Malik the Umayyad Caliph Who Built Dome of Rock
