The Abbasid Revolution (750 CE)
The Abbasids overthrew the Umayyads through a revolution that began in Khurasan (eastern Iran/Central Asia) — far from the Arab heartland. Their slogan: “al-ridha min al Muhammad” (the approved one from the family of Muhammad) — deliberately ambiguous, attracting both Shi’a supporters who thought they meant the ‘Alid family and proto-Abbasid supporters. When the Abbasids took power, they pivoted to ‘Abbasid legitimacy, betraying the ‘Alid element — a betrayal that deepened the Shi’a/Sunni rift.
The last Umayyad caliph, Marwan II, fled to Egypt and was killed. Abbasid agents allegedly massacred the Umayyad princes at a feast — though one survivor, ‘Abd al-Rahman I, escaped to Spain and founded the Umayyad emirate of al-Andalus (756 CE).
The Golden Age (750-950 CE)
Al-Mansur (r. 754-775): founded Baghdad as the circular city (“City of Peace”), became the world’s largest city within a generation.
Harun al-Rashid (r. 786-809): the caliph of 1001 Nights fame; his reign saw the peak of Abbasid cultural power; exchanged gifts with Charlemagne.
Al-Ma’mun (r. 813-833): founded the Bayt al-Hikma (House of Wisdom) — a systematic translation project that rendered Greek philosophy, medicine, mathematics, and astronomy into Arabic.
The Mu’tazilite debate: Al-Ma’mun embraced Mu’tazilite theology and imposed the doctrine of the khalq al-Quran (createdness of the Quran) — creating the famous Mihna (inquisition) during which Ahmad ibn Hanbal was imprisoned for refusing to capitulate. Ibn Hanbal’s resistance became the founding act of Hanbali identity.
The Ismaili Fatimid Challenge
The Fatimid Ismaili caliphate (909-1171 CE), based in Cairo, challenged Abbasid legitimacy directly. For the Abbasids, the Fatimids were heretical rebels; for the Fatimids, the Abbasids were usurpers. The rivalry was theological, political, and intellectual.
The Mongol End (1258 CE)
Hulagu Khan’s Mongol army besieged and sacked Baghdad in 1258 CE. The last Abbasid caliph, al-Musta’sim, was executed. The Tigris ran black with ink from the manuscripts thrown into it, red with blood. Eyewitness accounts describe 200,000-800,000 dead. The largest library complex in the medieval world was destroyed.
See also: Bohra History, Fatimid Caliphate, Khilafa, Khilafa Rashida, Al Ghazali, Kalam