The institution of slavery in West Central Africa predated the arrival of Europeans in the late 15th century, though there is limited information about its nature and extent or the gender and age dynamics prior to that period. Slavery in different West Central African societies in the 16th and 17th centuries was broadly defined as the legal and social outsider status of people originating from different states or chiefdoms and brought under captivity as a result of raids or wars, the payment for taxes from tributary states and chiefdoms, punishment for crimes such as adultery in royal circles, or direct purchase. This has been identified as lineage slavery and was distinct from the Atlantic slave trade.
Yet, the characteristics of slavery changed throughout the centuries. In the 16th and 17th centuries, local captives could become part of the kin of their owners after a process of integration in their new host society. They turned into insiders, even in instances in which they retained their enslaved status. However, from the 17th century, the expansion of the Atlantic slave trade and Portuguese colonialism resulted in a growing demand for captives, transforming the relations between captives and enslavers. The increasing presence of enslavers and their demand for different supplies, such as foodstuffs, resulted in a greater demand for labor in Portuguese colonial settlements, vassal chiefdoms, and autonomous states. Violence increased and individual kidnapping became the main method of enslavement, though warfare persisted as a method of capture well into the mid-19th century. Relations of dependency were increasingly disrupted and local captives became more vulnerable to deportation to other areas of West Central Africa and different parts of the world. Furthermore, the risk for insiders to be enslaved, re-enslaved, or deported increased, contributing to the redefinition of the meaning of slavery. Finally, following the prohibition of slavery by Portuguese colonial law in 1876, other forms of forced labor resembling slavery in varied ways emerged and were practiced until the third quarter of the 20th century. Resistance persisted throughout.
