 McIntosh states that the emergence of caste systems likely occurred much earlier in the West African societies such as Soninke, Mande, Malinke, Wolof, and others.She places the development and spread of castes in these societies to about the 10th-century, because the slave capture, slave trade and slave holding by elite families was an established institution in West Africa by then, and slavery created a template for servile relationships and social stratification of human beings.The linguistic evidence suggests that stratification structure and words relating to caste system and slavery likely were shared between the many ethnic groups, and possibly some others such as the Dogon people of West Africa.