Zanj—the Arabic meaning "Land of the Blacks"…
869 CE
Zanj—the Arabic meaning "Land of the Blacks" or "Land of the Negroes"—is a name used by medieval Arab geographers to refer to both a certain portion of the coast of East Africa and its inhabitants, Bantu-speaking peoples called the Zanj.
The seaboard is also the origin of the place name "Zanzibar Arabic”.
In recent decades, a number of Basran landowners had brought several thousand Zanj) into southern Iraq to drain the salt marshes east of Basra.
The landowners subject the Zanj, who generally speak no Arabic, to heavy slave labor in the salt flats and on the sugarcane and cotton plantations of southwestern Persia, providing them with only minimal subsistence.
In September 869, 'Ali ibn Muhammad, a Persian claiming descent from 'Ali, the fourth caliph, and Fatimah, Muhammad's daughter, gains the support of several slave-work crews, which can number from five hundred to five thousand men, by pointing out the injustice of their social position and promising them freedom and wealth.
'Ali's offers become even more attractive with his subsequent adoption of a Kharijite religious stance: anyone, even an enslaved East African, could be elected caliph, and all non-Kharijites are infidels threatened by a holy war.
Zanj forces grow rapidly in size and power, absorbing the well-trained enslaved East African contingents that defect from the defeated caliphal armies, along with some disaffected local peasantry.
In October 869, they defeat a Basran force, and soon afterward a Zanj capital, al-Mukhtara, is built on an inaccessible dry spot in the salt flats, surrounded by canals.