Zanj Rebellion

Wealthy Basrans had acquired the marshlands of lower Iraq and set gangs of slaves to strip away the salty topsoil to make them arable, or to work in the salt flats; their working and living conditions were miserable. Arabic writers called such labourers Zanj, the name used for the peoples of the East African coast, but modern historians think that the term here covered Africans of various origins, brought through the Indian Ocean slave trade or captured, and some, like Ghada Talhami, see the revolt as a wider religious and social rising that drew in people of many kinds; Bedouin tribes of the region also joined the rebels. Their leader, Ali ibn Muhammad, had already failed to raise revolts in Bahrayn and in Basra; in September 869 he began to free and recruit the marsh slaves, promising them wealth. He adopted the Kharijite doctrine that the worthiest man should rule, even a slave, and put Kharijite formulas on his banners and coins.

Fighting in the marshes and along the canals, the rebels built a fortified capital, al-Mukhtara, south of Basra, took al-Ubulla (870) and the market town of al-Ahwaz (871), and in September 871, after a long blockade, stormed Basra, burning the city and massacring its people. The caliphate, crippled by the ‘Anarchy at Samarra’ and then fighting the Saffarid Ya'qub ibn al-Layth, could not stop them: al-Muwaffaq’s campaign of 872 failed, and by 879 they had sacked Wasit and Ramhurmuz and advanced up the Tigris to within some 80 km of Baghdad.

From late 879 al-Muwaffaq and his son Abu al-Abbas, the future caliph al-Mu'tadid, drove the rebels out of Iraq and Khuzistan, and in February 881 they laid siege to al-Mukhtara, offering generous terms to all who surrendered. The city fell in August 883; Ali ibn Muhammad was killed, and his head was carried along the canals on a boat and later paraded in Baghdad. Medieval writers give huge casualty figures — al-Mas'udi’s ‘moderate’ estimate of 500,000 dead, which he himself called empty conjecture — that modern historians regard as gross exaggerations; the main source is the detailed narrative of al-Tabari. By tying down the caliphate’s armies for fourteen years, the war helped the Saffarids in Iran and Ahmad ibn Tulun in Egypt to make themselves independent.