Paul Baepler’s White Slaves, African Masters: An Anthology of American Barbary Captivity Narratives lists a collection of essays by nine American captives held in North Africa. According to his book, there were more than 20,000 white Christian slaves by 1620 in Algiers alone; their number swelled to more than 30,000 men and 2,000 women by the 1630s. There were a minimum of 25,000 white slaves at any time in Sultan Moulay Ismail’s palace, records Ahmed ez-Zayyani; Algiers maintained a population of 25,000 white slaves between 1550 and 1730, and their numbers could double at certain times. During the same period, Tunis and Tripoli each maintained a white slave population of about 7,500. The Barbary pirates enslaved some 5,000 Europeans annually over a period of nearly three centuries.