Slavery in Algeria formed part of overlapping Mediterranean and trans-Saharan systems. Before the French conquest, the Regency of Algiers received captives through corsair warfare and coastal raiding; some Christian captives were ransomed, while others were sold or put to labor. Muslim captives were also enslaved on the Christian side of the Mediterranean, so the sea was a shared zone of capture rather than a boundary between a slave and a free society. Algiers was also connected to Saharan routes that brought enslaved people from sub-Saharan Africa for household, agricultural, military, and sexual labor.
French conquest began in 1830 but did not create a single immediate transition from slavery to freedom. France's decree of 27 April 1848 abolished slavery throughout its colonies and possessions, including French-ruled Algeria. Military conquest, uneven territorial control, and local practice complicated implementation. Legal abolition should also be distinguished from coercive labor imposed under colonial rule.