THE ABBASID CALIPHATE

ʿAbbasid caliphate, second of the two great dynasties of the Muslim empire of the caliphate. It overthrew the Umayyad caliphate in 750 CE and reigned as the Abbasid caliphate until it was destroyed by the Mongol invasion in 1258.

The name is derived from that of the uncle of the Prophet Muhammad, al-ʿAbbās (died c. 653) of the Hashemite clan of the Quraysh tribe in Mecca. From about 718, members of his family worked to gain control of the empire from the Umayyads and, by skillful propaganda, won much support, especially from Shiʿi Arabs and Persians in Khorāsān. Open revolt in 747, under the leadership of Abū Muslim, led to the defeat of Marwān II, the last Umayyad caliph, at the Battle of the Great Zab River (750) in Mesopotamia and to the proclamation of the first Abbasid caliph, Abū al-ʿAbbās al-Saffāḥ. 

Under the Abbasids the caliphate entered a new phase. Instead of focusing, as the Umayyads had done, on the West—on North Africa, the Mediterranean, and southern Europe—the caliphate now turned eastward. The capital was moved to the new city of Baghdad, and events in Persia and Transoxania were closely watched. For the first time, the caliphate was not coterminous with Islam. In Egypt, North Africa, Spain, and elsewhere, local dynasties claimed caliphal status. With the rise of the Abbasids, the base for influence in the empire became international, emphasizing membership in the community of believers rather than Arab nationality. Since much support for the Abbasids came from Persian converts, it was natural for the Abbasids to take over much of the Persian (Sasanian) tradition of government. Support by pious Muslims likewise led the Abbasids to acknowledge publicly the embryonic Islamic law and to profess to base their rule on the religion of Islam.

Between 750 and 833 the Abbasids raised the prestige and power of the empire, promoting commerce, industry, arts, and science, particularly during the reigns of al-Manṣūr, Hārūn al-Rashīd, and al-Maʾmūn. Their temporal power, however, began to decline when al-Muʿtaṣim introduced non-Muslim Berber, Slav, and especially Turkish mercenary forces into his personal army. Although these troops were converted to Islam, the base of imperial unity through religion was gone, and some of the new army officers quickly learned to control the caliphate through assassination of any caliph who would not accede to their demands.

The power of the army officers had already weakened through internal rivalries when the Iranian Būyids entered Baghdad in 945, demanding of al-Mustakfī (944–946) that they be recognized as the sole rulers of the territory they controlled. This event initiated a century-long period in which much of the empire was ruled by local dynasties. In 1055 the Abbasids were overpowered by the Seljuqs, who took what temporal power may have been left to the caliph but respected his position as the titular leader, restoring the authority of the caliphate, especially during the reigns of al-Mustarshid (1118–35), al-Muqtafī, and al-Nāṣir. Soon after, in 1258, the dynasty fell during a Mongol siege of Baghdad.

The Abbasids, descendants of an uncle of Muhammad, owed the success of their revolt in large part to their appeal to various pietistic, extremist, or merely disgruntled groups and in particular to the aid of the Shiʿah, who held that the Caliphate belonged by right to the descendants of ʿAlī. That the Abbasids disappointed the expectations of the Shiʿah by taking the Caliphate for themselves left the Shiʿah to evolve into a sect, permanently hostile to the Sunni majority, that would periodically threaten the established government by revolt. The first Abbasid caliph, al-Saffāḥ (749–754), ordered the elimination of the entire Umayyad clan; the only Umayyad of note who escaped was ʿAbd al-Raḥman, who made his way to Spain and established an Umayyad dynasty that lasted until 1031.

The period 786–861, especially the caliphates of Hārūn (786–809) and al-Maʾmūn (813–833), is accounted the height of Abbasid rule. The eastward orientation of the dynasty was demonstrated by al-Manṣūr’s removal of the capital to Baghdad in 762–763 and by the later caliphs’ policy of marrying non-Arabs and recruiting Turks, Slavs, and other non-Arabs as palace guards. Under al-Maʾmūn, the intellectual and artistic heritage of Iran (Persia) was cultivated, and Persian administrators assumed important posts in the Caliphate’s administration. After 861, anarchy and rebellion shook the empire. Tunisia and eastern Iran came under the control of hereditary governors who made token acknowledgment of Baghdad’s suzerainty. Other provinces became less-reliable sources of revenue. The Shiʿah and similar groups, including the Qarmaṭians in Syria and the Fāṭimids in North Africa, challenged Abbasid rule on religious as well as political grounds.

Competing claims:
Abbasid power ended in 945, when the Būyids, a family of rough tribesmen from northwestern Iran, took Baghdad under their rule. They retained the Abbasid caliphs as figureheads. The Samanid dynasty that arose in Khorāsān and Transoxania and the Ghaznavids in Central Asia and the Ganges River basin similarly acknowledged the Abbasid caliphs as spiritual leaders of Sunni Islam. On the other hand, the Fāṭimids proclaimed a new caliphate in 920 in their capital of Al-Mahdiyyah in Tunisia and castigated the Abbasids as usurpers; the Umayyad ruler in Spain, ʿAbd al-Raḥmān III, adopted the title of caliph in 928 in opposition to both the Abbasids and the Fāṭimids. Nominal Abbasid authority was restored to Egypt by Saladin in 1171. By that time the Abbasids had begun to regain some semblance of their former power, as the Seljuq dynasty of sultans in Baghdad, which had replaced the Būyids in 1055, itself began to decay. The caliph al-Nāṣir (1180–1225) achieved a certain success in dealing diplomatically with various threats from the east, but al-Mustaʿṣim (1242–58) had no such success and was murdered in the Mongol sack of Baghdad that ended the Abbasid line in that city. A scion of the family was invited a few years later to establish a puppet caliphate in Cairo that lasted until 1517, but it exercised no power whatsoever. From the 13th century onward a variety of rulers outside Cairo also included caliph among their titles, although their claims to universal leadership of the Muslim community seem to have been more notional than real.

By The Editors of Encyclopaedia Britannica.  Last Updated: Oct 6, 2022. Britannica, The Editors of Encyclopaedia. "ʿAbbasid caliphate". Encyclopedia Britannica, 6 Oct. 2022, https://www.britannica.com/topic/Abbasid-caliphate. Accessed 18 November 2022.