Abbāsid Caliphate

Within the ‘Abbāsid period (750–1258), Islam developed into a world religion, transcending ethnic boundaries. For five centuries, the ‘Abbāsid caliphs were recognized by most Sunnī Muslims as at least their nominal rulers. Iraq, Syria, Egypt, and North Africa became Arabized during this period, while Iran more successfully retained its indigenous identity, experiencing a cultural renaissance in the 10th and 11th centuries. Meanwhile, most dhimmis (a non-Muslim subject of a state governed in accordance with the Shari'a law), along with the newly arrived Turks, adopted Islam.

The ‘Abbāsid period began after a rebellion arising in Khurasan in 747 toppled the last Umayyad caliph, replacing him not with a descendant of Muhammad XII, as many expected, but with al-Saffāh (750–754), a descendant of the Prophet's uncle al-‘Abbās. Al-Mansūr (754–775) built Baghdad as his new capital, and there the caliphs adopted the traditions of pre-Islamic Sasanian bureaucracy and autocracy. ‘Abbāsid power reached its zenith under Harun al-Rashid (786–809), but his reign was followed by civil war, and provincial governors increasingly established independent dynasties. The Shi'a Fātimids even proclaimed a rival caliphate (910), eventually basing it in Cairo (969–1171).

Al-Mu'tasim (833–842) and subsequent caliphs recruited foreign soldiers, often Turkish slaves (singular ghulām or mamlūk), but their assassination of al-Mutawakkil (847–861) started a period of instability. From 936, real authority in Baghdad was held by a commander-in-chief (amīr al-umara’), a position taken over by the Shi'a Būyids in 945. At least their successors from 1055, the Turkish Seljuk sultan (singular sultan, meaning “authority”), having already conquered the eastern ‘Abbásid lands, were vigorous defenders of Sunnī Islam against the Fátimids and the Byzantines.

Seeking a symbol of communal legitimacy, the ulema somewhat ambivalently endorsed early ‘Abbásid rule while expounding Islamic standards of government and personal conduct in works of jurisprudence (fiqh) based on the Qur'an and sunna. They defeated an attempt by al-Ma'mūn (813–833) and his immediate successors to make the caliphs themselves arbiters of Islamic doctrine and practice, largely securing that role for themselves. Alongside and sometimes in tension with the teachings of conservative Sunnī scholars, though, there developed philosophical, theological, and mystical interpretations of Islam—the last of which would profoundly influence popular religion and provide a basis for new forms of religious association, the Sufi confraternities (singular tarīqah). As the dynasty declined, Sunnī apologists argued—in opposition to the increasingly coherent Shi'a sects—that an impotent caliph could, indeed must, fulfill his responsibilities by delegating them to the sultans and the ulema.

When Saljuk authority fragmented in the 12th century, numerous ephemeral principalities and some more substantial successor states emerged under contending warlords who offered at best nominal loyalty to the caliph. The last significant ‘Abbāsid, al-Nāsir (1180–1225), was little more than one petty ruler among others. After the Mongols sacked Baghdad and killed most of the family (in 1258), the mamlūk regime in Cairo maintained a shadow ‘Abbāsid caliphate (1261–1517) until the Ottoman conquest. It was not widely recognized at the time, but later it was said to have conferred the caliphal title on the Ottoman sultans.