Ibrahim, due to his brother Muhammad's rushed actions, had failed to coordinate his own uprising with his brother's, and had only declared himself two weeks before Muhammad's death, on November 23, 762.
Ibrahim's revolt at first had met with quick success, securing control over Ahwaz, Fars and Wasit, and his army register (diwan) was said to number one hundred thousand names.
When the news of Muhammad's death arrived, the rebels had acclaimed Ibrahim as his successor.
Ibrahim now was faced with a choice: a group of dedicated Alid supporters, which had managed to escape from Kufa, urged him to march on the city, while the Basrans preferred to stay in place and reach a negotiated settlement.
This dissension is indicative of the disparate nature of Ibrahim's supporters.
The Alid cause is fractured into several competing groups with different political objectives, and Ibrahim represents the Hasanid branch only.
The Husaynids refuse to take part in an uprising, while Ibrahim quarreswith the Zaydi branch on everything from political objectives and leadership to the tactics to be followed or the provisioning of their troops.
Elsewhere, support for the uprising is cautious and most Alid supporters adopt a wait-and-see attitude, limiting themselves to verbal support or contributions of money.
Al-Mansur in the meantime uses his time more effectively: he mobilized troops in Syria and Iran and brings them to the Iraq, and recalls Isa Ibn Musa from Medina to lead them.
Finally, Ibrahim decides to march on Kufa, but on the way he abandons this plan and turns back.
Instead of returning to Basra, however, he encamps at Bakhamra, a location on the road between the two cities.
Here, on 21 January, Ibrahim with his troops, reduced by defections to some fifteen thousand men, confronts the Abbasid army under Isa ibn Musa.
Isa's vanguard is at first beaten, but the battle ends in a crushing Abbasid victory.
Ibrahim himself is heavily wounded and escapes with a handful of supporters.
