They then sold them throughout the Ottoman Empire and the North African Barbary states of Morocco, Algiers, Salee, Oran, Tunis, Tripoli and Bacra, not stopping until forced to by the Barbary Pirate War of 1816.
Charles Sumner wrote:
"The Saracens, with the Koran and the sword, potent ministers of conversion, next broke from Arabia, as the messengers of a new religion,
and pouring along these shores, diffused the faith and doctrines of Mohammed ... even ... entered Spain, and ... at Roncesvalles ... overthrew the embattled chivalry of the Christian world led by Charlemange. (The Song of Roland) ...
Algiers, for a long time the most obnoxious place in the Barbary States of Africa, the chief seat of Christian slavery ... the wall of the barbarian world ..."