The Zanj Rebellion or the Negro Rebellion was the culmination of series of small revolts. It took place near the city of Basra, located in present-day southern Iraq, over a period of fifteen years (AD 869–883). The insurrection is believed to have involved enslaved Bantus (Zanj) that had originally been captured from the African Great Lakes region and areas further south in East Africa.> It grew to involve many slaves and free men who were imported from across the Muslim empire and claimed over ""tens of thousands of lives in lower Iraq"". The precise composition of the rebels is debated among historians, both as regards their identity and as to the proportion of slaves and free among them – available historical sources being open to various interpretations. The revolt was said to have been led by Ali bin Muhammad, who claimed to be a descendant of Caliph Ali ibn Abu Talib. Several historians, such as al-Tabari and al-Masudi, consider this revolt one of the ""most vicious and brutal uprisings"" of the many disturbances that plagued the Abbasid central government.The Zanj Revolt helped Ahmad ibn Tulun to create an independent state in Egypt. It is only after defeating the Zanj Revolt that the Abbasids were able to turn their attention to Egypt and end the Tulunid dynasty with great destruction.