Kidnapping and prisoners of war were the most common sources of African slaves, although indentured servitude or punishment also resulted in slavery.
[1][2] The many alternative methods of obtaining human beings to work in indentured or other involuntary conditions, as well as technological and cultural changes, have made slave raiding rarer.
Other than the element of slavery being present, such violent seizure of a resource does not differ from similar raids to gain food or any other desired commodity.
[citation needed] Slave raiding was a large and lucrative trade on the coasts of Africa, in ancient Europe, Mesoamerica, and in medieval Asia.
[citation needed] The act of slave raiding involves an organised and concerted attack on a settlement with the purpose of taking the area's people.
[4] During the warfare between Rome and the Byzantine Empire in Southern Italy in the 9th-century the Saracens made Southern Italy a supply source for a slave trade to Maghreb by the mid 9th-century; the Western Emperor Louis II complained in a letter to the Byzantine Emperor that the Byzantines in Naples guided the Saracens in their raids toward South Italy and aided them in their slave trade with Italians to North Africa, an accusation noted also by the Lombard Chronicler Erchempert.
[6] The Saracens captured the Baleares in 903, and made slave raids also from this base toward the coasts of the Christian Mediterranean and Sicily.
[15] Portuguese coastal raiders found that raiding was too costly and often ineffective and opted for established commercial relations.
[18] These kingdoms relied on a militaristic culture of constant warfare to generate the great numbers of human captives required for trade with the Europeans.
[26] West Transvaal Boers and others procured women and children as slaves and used them as domestic servants and plantation workers.