the Seleucid dynasty (63 BC), Bactria, Parthia, and the Kushans took control in succession. In 53 BC, some 10,000 Roman prisoners of war from the Battle of Carrhae appear to have been deported to Merv. Merv was a major city of Buddhist learning, with Buddhist monastery temples for many centuries until its Islamisation. At the site of Gyaur Kala and , Buddhism was followed and practised often at the local Buddhist stupas. Sasanian era After the Sassanid Ardashir I (220–240 AD) took Merv, the study of numismatics picks up the thread: the unbroken series of coins originally minted at Merv document a long unbroken direct Sassanian rule of almost four centuries. During this period Merv was home to practitioners of various religions beside the official Sassanid Zoroastrianism, including Buddhists, Manichaeans, and Christians of the Church of the East. Between the 5th and 11th centuries, Merv served as the seat of an East Syrian metropolitan province. The first bishop was Barshabba (c.360/424). The Hephthalite occupation from the end of the 5th century to 565 AD briefly interrupted Sassanid rule. Arab conquest and influence Sassanian rule ended when the last Sassanian ruler, Yazdegerd III (632–651) was killed near the city and the Sassanian military governor surrendered to the approaching Arab army. Representatives of the caliph, Umar occupied the city, which became the capital of the Umayyad province of Khorasan. In 671, Ziyad ibn Abi Sufyan sent 50,000 Arab troops to Merv as a colony. This colony retained its native Kufan sympathies and became the nucleus of Khurasan. Using the city as their base, the Arabs, led by Qutayba ibn Muslim from 705 to 715, brought large parts of Central Asia, including Balkh, Bokhara, and Fergana under subjection. Merv, and Khorasan, in general, became one of the first parts of the Persian-speaking world to become majority-Muslim. Arab immigration to the area was substantial. A Chinese man captured at Talas, Du Huan, was brought to Baghdad and toured the caliphate. He observed that in Merv, Khurasan, Arabs and Persians lived in mixed concentrations. Merv gained renewed importance in February 748 when the Iranian general Abu Muslim (d. 755) declared a new Abbasid dynasty at Merv, expanding and re-founding the city, and, in the name of the Abbasid line, used the city as a base of rebellion against the Umayyad caliphate. After the Abbasids established themselves in Baghdad, Abu Muslim continued to rule Merv as