The battle was the culmination of several weeks of fighting between the Zanj rebels and local defenders in the villages and canals of southern Iraq.

The battle was a major victory for the Zanj, and it forced the Abbasid government to take a more direct role in the campaign against the rebels.

[3] 'Ali was able to quickly gather a major following, especially among the black slaves who had been employed to cultivate the lands in the area of the modern Shatt al-Arab.

[4] Soon after the proclamation of the rebellion, the Zanj spread out among the districts of the lower Tigris and Karun rivers and advanced against several of the villages in the region.

[5] In the early stages of the rebellion, the defense of the towns of lower Iraq was largely handled by provincial garrisons, local volunteers and slaves, with the central government in Samarra initially contributing little or no troops to stop the Zanj.

Militia groups composed of men from Basra, al-Ubullah and other towns were soon organized, and set off to fight off the Zanj in an attempt to protect their communities and property.

Approaching the city from the southeast, the Zanj soon encountered two regiments consisting of soldiers, Arab tribesmen and men from the factions of Basra.

He stayed at al-Mu'alla overnight, and in the following morning he inspected the troops again, finding that a thousand more men had returned during the night.

After reprimanding one of the men who had failed to immediately return to the camp, he dispatched Muhammad ibn Salm to speak to the Basrans and attempt to garner support among them.

The force consisted of archers and volunteers from the various city factions; Hammad al-Saji, a veteran sailor, was appointed to lead the expedition.

[11] The advance of the Basran army was quickly reported by 'Ali ibn Muhammad's scouts, who returned to the Zanj camp to deliver the news.

The ambushers then emerged from their hiding places and fell upon the enemy from the rear, indiscriminately attacking the foot soldiers and unarmed people alike.

The alarmed residents of the city decided to write to the caliph al-Muhtadi in Samarra, urging him to send government troops to the region.

The caliph responded by sending Ju'lan al-Turki with reinforcements to the Basra area, thereby expanding the involvement of central government in the effort to combat the Zanj.