Maslama commanded the summer expedition against the Byzantine Empire in 739, taking control of al-Matamir, the cavernous southern half of Cappadocia, and besieged and captured Ancyra (modern Ankara). Maslama's victories marked the last Umayyad captures of a Byzantine fortress or town. The following summer the Umayyads launched the largest expedition against the Byzantines during Hisham's reign. The main expedition was led by Maslama's brother Sulayman, and Maslama may have commanded a separate expedition during the same year. The Umayyads raided throughout western Anatolia but were beaten back by the Byzantines without any territorial gains, while two of the Caliphate's leading generals, Abdallah al-Battal and Malik ibn Shu'ayb were slain by the forces of Byzantine emperor Leo III.