The slave trade in East Africa appears to have been active to varying degrees before the arrival of Islam with the Arabs. References to African slaves can be found in a number of Chinese texts dating back to at least 1200, meaning that the practice was certainly well established before the arrival of the Portuguese in around 1500. The Arab slave trade was centred on the coast where Islam had become established, with slaves being sourced from pagan communities towards the inner continent because the slavery of fellow Muslims was forbidden under Islamic law. Arab settlement of the coastal regions and intermarriage with the local Bantu people led to the establishment of regional Swahili city-states and the Kilwa Sultanate. Female slaves made up the majority of the Arab slave trade and were often used as concubines, whilst male slaves tended to be used as soldiers or manual workers elsewhere in the Islamic world.
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