Funj

It is known that the Funj rose from southern Nubia (present-day southern Sudan) to overthrow the kingdom of Alodia, but their origins before that remain obscure and disputed. The Funj themselves claimed descent from the Umayyad dynasty through those who escaped slaughter at the hands of the Abbasids and fled to Abyssinia. A currently more accepted theory is that they are Nubians who mixed with Arabs.

2014, Anders Breidlid, et al. (editors), A Concise History of South Sudan, Fountain Publishers, Revised Edition, page 52, Slavery was the cornerstone of Funj wealth and power. In the 18ᵗʰ century, the Funj rulers built up a military division of slaves from foreign lands who were loyal only to themselves. By the mid 18ᵗʰ century, these Funj rulers were very powerful.