Maslama ibn Abd al-Malik
Under the more aggressive Caliph Hisham ibn Abd al-Malik (), the Arab raids became more substantial affairs and were led by some of the Caliphate's most capable generals, including princes of the Umayyad dynasty, such as Maslama ibn Abd al-Malik or Hisham's own sons Mu'awiyah, Maslama, and Sulayman. Gradually, however, the Muslim successes became fewer, especially as their resources were drawn into the mounting conflict with the Khazars in the Caucasus. The raids continued, but the Arab and Byzantine chroniclers mention fewer successful captures of forts or towns. Nevertheless, in 737 a major victory over the Khazars allowed the Arabs to shift their focus and intensify their campaigns against Byzantium. Thus in 738 and 739 Maslamah ibn Hisham led successful raids, including the capture of the town of Ancyra. For the year 740, Hisham assembled the largest expedition of his reign, appointing his son Sulayman to lead it.