 After the accession of Caliph Hisham (r. 723–743), the scale and ambition of the Muslim raids grew.One of the most prominent Umayyad leaders in these campaigns was Hisham's son Mu'awiya, who led expeditions in 725 and 726, the first of which went as far west as Dorylaion.In summer 727, another large-scale invasion was led by Mu'awiya, with Abdallah al-Battal heading the vanguard of the army.