The revolution that established the Abbasids represented a triumph of the Islamic Hejazi elements within the empire; the Iranian revival was yet to come. Nevertheless, Abbasid concern with fostering eastern Islam made the new caliphs willing to borrow the methods and procedures of statecraft employed by their Iranian predecessors. At Damascus the Umayyads had imitated Sasanian court etiquette, but at Baghdad Persianizing influences went deeper and aroused some resentment among the Arabs, who were nostalgic for the legendary simplicity of human relations among the desert Arabs of yore. Self-conscious schools of manners grew up in the new metropolis, representing the competitive merits of the Arabs’ or Persians’ ancient ways. To counter the widespread Arab chauvinism still present after the Abbasid revolution, there arose a literary-political movement known as the shuʿūbiyyah, which celebrated the excellence of non-Arab Muslim peoples, particularly the Persians, and set the stage for the resurgence of Iranian literature and culture in the decades to come. Regard for poetry—the Arabs’ vehicle of folk memory—increased, and minds and imaginations were quickened. Philosophical enquiry was developed out of the need for precision about the meaning of Holy Writ and for the establishment of the authenticity of the Prophet’s dicta, collected as Hadith—sayings traditionally ascribed to him and recollected and preserved for posterity by his companions. An amalgam known as Islamic civilization was thus being forged in Baghdad in the 8th and 9th centuries. The Iranian intellect, however, played a conspicuous part in what was still an Arab milieu. Works of Indian provenance were translated into Arabic from Pahlavi, the written language of Sasanian Iran, notably by Ibn al-Muqaffaʿ (c. 720–757). The wisdom of both the ancient East and West was received and discussed in Baghdad’s schools. The metropolis’s outposts confronted Byzantium as well as infidel marches in Afghanistan and Central Asia. Cultural influences came from both directions. Curiosity in the pursuit of knowledge had been enjoined by the Prophet “even as far as China.” This cosmopolitanism was not new to the descendants of the urban Arabs of Mecca or to the Iranians, whose land lay across the routes from the Pacific to the Mediterranean. Both peoples knew how to transmute what was not originally their own into forms that were entirely Islamic. Islam had liberated men of the scribal and mercantile classes who in Iran had been subject to the dictates of a taboo-ridden and excessively ritualized Zoroastrianism and who in Arabia had been inhibited by tribal feuds and prejudices.

Despite the development of a distinctive Islamic culture, the military problems of the empire were left unsolved. The Abbasids were under pressure from the infidel on several fronts—Turks in Central Asia, pagans in India and in the Hindu Kush, and Christians in Byzantium. War for the faith, or jihad, against these infidels was a Muslim duty. But, whereas the Umayyads had been expansionists and had seen themselves as heads of a military empire, the Abbasids were more pacific and saw themselves as the supporters of more than an Arab, conquering militia. Yet rebellions within the imperial frontiers had to be contained and the frontiers protected.

Rebellion within the empire took the form of peasant revolts in Azerbaijan and Khorāsān, coalesced by popular religious appeals centered on men who assumed or were accorded mysterious powers. Abū Muslim—executed in 755 by the second Abbasid caliph, al-Manṣūr, who feared his influence—became one such messianic figure. Another was al-Muqannaʿ (Arabic: “the Veiled One”), who used Abū Muslim’s mystique and whose movement lasted from 777 to 780. The Khorram-dīnān (Persian: “Glad Religionists”), under the Azerbaijani Bābak (816–838), also necessitated vigorous military suppression. Bābak eluded capture for two decades, defying the caliph in Azerbaijan and western Persia, before being caught and brought to Baghdad to be tortured and executed. These heresiarchs revived such creeds as that of the anti-Sasanid religious leader Mazdak (died 528 or 529), expressive of social and millenarian aspirations that were later canalized into Sufism on the one hand and into Shiʿism on the other.

Sīstān, Iran’s southeastern border area, had a tradition of chivalry as the ancient homeland of Iranian military champions. Their tales passed to posterity collectively in the deeds of Rostam, son of Zāl, in Ferdowsī’s Shāh-nāmeh, the Persian national epic. On the route to India, Sīstān was also a center of trade. Its agrarian masses were counterbalanced by an urban population whose economy could be bolstered by plunder gained through military forays into still non-Muslim areas under the rule of the southern Hephthalites—the Zunbīls of the Hindu Kush’s southwestern flanks—whose command of trade routes with India had to be contested when the existing partnership in this command broke down.

Early exploitation of the province’s agriculture by Arab governors had, however, debilitated the rural life, and Khārijites, who found refuge in Sīstān from the Umayyads, organized or attracted bands of local peasants and vagabonds who had strayed south from Khorāsān. The presence of these groups indicates agricultural depression following the first century of rule by nonagricultural Arabs who had failed to grasp the needs of the Iranian cultivators. Khārijite bands isolated the cities and threatened their supplies. Sīstān needed an urban champion who could come to terms with the Khārijites and divert them to what could legitimately be termed jihad across the border, forming the gangsters into a well-disciplined loyal army. Such a man was Yaʿqūb ibn Layth, who founded the Ṣaffārid dynasty, the first purely Iranian dynasty of the Islamic era, and threatened the Muslim empire with the first resurgence of Iranian independence.