 This caste system, however, wasn't as elaborate in places like northern Nigeria, Eastern Niger or Cameroon.According to some estimates, by the late 19th century, slaves constituted about 50% of the population of the Fulɓe-ruled Adamawa Emirate, where they were referred to as "jeyaɓe" (singular "jeyado").Though very high, these figures are representative of many other emirates of the Sokoto Caliphate, of which Adamawa formed a part.