Qutayba ibn Muslim
Khorasan and Sistan, where Zoroastrianism was well-established, were conquered. The Arabs had begun to move towards the lands east of Persia and in 652 they captured the city of Herat, establishing an Arab governor there. The Muslim frontier in modern Afghanistan had become stabilized after the first century of Hijri calendar as the relative importance of the Afghan areas diminished. From historical evidence, it appears Tokharistan (Bactria) was the only area heavily conquered by Arabs where Buddhism flourished. Balkh's final conquest was undertaken by Qutayba ibn Muslim in 705. Hui'Chao, who visited around 726, mentions that the Arabs ruled it and all the inhabitants were Buddhists.