The roots of the conflict ran deep, back to the death of the Prophet Muhammad in 632 CE. A significant faction within the early Muslim community believed that only the Prophet's own family -- the Ahl al-Bayt -- possessed the divine guidance needed to rule justly. These proto-Shi'a sentiments crystallized around Ali, the Prophet's cousin and son-in-law, and his descendants. But Ali's line suffered a century of defeats: the catastrophe at Karbala in 680, the failed revolt of Zayd ibn Ali in 740. Iraq, and Kufa in particular, became the heartland of Alid sympathies, a place where grief over these losses ran through the culture like an underground river.

When the Abbasids overthrew the Umayyad dynasty in 750, they did so using language carefully designed to attract Alid supporters. Their rallying cry called for "a chosen one from the Family of Muhammad" without specifying which branch of the family would rule. The Abbasids claimed legitimacy through the Prophet's uncle Abbas, a connection that many Alids considered distant at best. Some sources suggest that the future Caliph al-Mansur himself had sworn an oath of allegiance to Muhammad ibn Abdallah back in 744, before the revolution. Whether or not this is true, the Hasanid brothers felt cheated. They refused to submit to what they saw as a usurpation, and they disappeared underground.

The first Abbasid caliph, al-Saffah, mostly ignored the fugitive brothers during his short reign from 750 to 754. His successor al-Mansur was not so tolerant. A methodical and ruthless ruler, al-Mansur launched a sustained campaign to find Muhammad and Ibrahim. In 758, he arrested their brother Abdallah when the man refused to reveal their hiding place. By early 762, he had rounded up their cousins and nephews. The captive Alids were taken to Kufa, where many of them perished. For the brothers still in hiding, the message was clear: submission or rebellion. There was no third option.

The brothers planned a simultaneous rising. Muhammad would seize Medina while Ibrahim took Basra. The coordination failed almost immediately. Muhammad launched his revolt in September 762, but Ibrahim did not rise until November. Al-Mansur moved swiftly, containing Muhammad's rebellion in the Hejaz and crushing it within weeks. Ibrahim had more initial success in southern Iraq, but his coalition fractured. Rival Shi'a factions argued over strategy and what a post-Abbasid order should look like. When Ibrahim finally marched toward Kufa, he reversed course and encamped at Bakhamra, on the road between Basra and Kufa. On January 21, 763, his army of roughly 15,000 men met the Abbasid forces under Isa ibn Musa. Ibrahim's vanguard won early clashes, but the main battle ended in total defeat. Ibrahim escaped with a handful of followers, mortally wounded. He died on February 14.

The aftermath was brutal. Al-Mansur launched sweeping reprisals against the Alids, imprisoning and killing many. Only his death brought a period of attempted reconciliation under his son al-Mahdi, which itself ended after another Alid uprising in 786. But the defeated family's story did not end at Bakhamra. Muhammad's surviving sons and brothers fled to the remotest edges of the caliphate, and some of them succeeded where the revolt had failed. Muhammad's half-brother Idris later escaped to Morocco -- not immediately after this revolt, but after the Battle of Fakhkh in 786 -- and founded the Idrisid dynasty. Other Alids established the Zaydid dynasty in Tabaristan, along the southern shores of the Caspian Sea. The repression that followed the revolt scattered the broader Alid family across the Islamic world, planting dynasties in places the Abbasids could not easily reach.