Excerpts from Books and Wikipedia
" . . . decided to expel the Moriscos--Muslim descendants who had converted to Christianity after the fall of Granada in 1492--from Spain. It is estimated that as many as 300,000 (about 4 percent of the Spanish population) were forced to leave, between 1609 and 1614, using ships that had been released from the war in the Netherlands. . . . But as Spain's war against the Ottoman Empire intensified in the 1560s, suspicion grew that the Moriscos were in league with Spain's Muslim enemies, especially the Barbary pirates who attacked Spanish shipping in the Mediterranean." [1001 Days]