 While it is unclear when and how the caste systems developed in Africa, they are not ancient and likely developed sometime between the 9th century and 15th century in various ethnic groups, probably in conjunction with the institution of slavery.The social stratification of the Amhara people of Ethiopia includes castes.According to Donald Levine – a professor of Sociology specializing in Ethiopian society, the Amhara society has consisted of high-ranking clans, low-ranking clans, caste groups (artisans), and slaves.