Endogamous artisan and musician groups are characteristic of over fifteen West African peoples, including the Manding, Soninke, Wolof, Serer, Fulani, Tukulor, Songhay, Dogon, Senufo, Minianka, Moors, and Tuareg. Castes appeared among the Malinke no later than 1300, and were present among the Wolof and Soninke, as well as some Songhay and Fulani populations, no later than 1500. All the West African castes ultimately developed from at most three centers, located among the Manding, Soninke, and/or Wolof. Migration is the key process explaining the current distribution of caste people. Formation of blacksmith and bard castes among the Manding may be related to the Sosso–Malinke war, described in the Sunjata epic, which led to the founding of the Mali empire. As they evolved over time, castes acquired secondary specializations or changed occupations, and moved up or down in rank relative to other social groups. Although marriage alliances took place within a caste or among a limited number of castes, castes did not form demographic isolates. Children of caste men and slave concubines had caste status, while free persons taken captive in war sometimes claimed to be caste members. Assimilation of local artisans to a caste may have occurred when caste institutions were first introduced into a given area.