 Thus, a professional army was established during Abd al-Malik's reign whose salaries derived from tax proceeds.The dependence on the Syrian army of his successors, especially Hisham (), scattered the army among the Caliphate's multiple and isolated war fronts, most of them distant from Syria.The growing strain and heavy losses inflicted on the Syrians by the Caliphate's external enemies and increasing factional divisions within the army contributed to the weakening and downfall of Umayyad rule in 750.