During the sixteenth and seventeenth centuries, Spanish authorities restricted emigration to the Americas to those who could prove they had been Catholic for at least three generations. In doing so, they hoped to instill religious orthodoxy in the colonies and believed Muslim converts, or Moriscos, would hamper efforts to convert indigenous people to Catholicism. Nevertheless, Moriscos secretly made the treacherous journey across the ocean, settling in the forbidden territories and influencing the nature of Spanish colonialism. Once landed, Morisco men and women struggled to define and practice their religion or pursue their trades, all while experiencing increasing anxiety about their place in the emerging Spanish empire. Many Moriscos were accused by authorities of descending from Muslims or practicing Islam in secret and turned to the courts to assert their legitimacy.

Forbidden Passages is the first book to document and evaluate the impact of Moriscos in the early modern Americas. Through close examination of sources that few historians have used—some one hundred cases of individuals brought before the secular, ecclesiastical, and inquisitorial courts—Karoline P. Cook shows how legislation and attitudes toward Moriscos in Spain assumed new forms and meanings in colonial Spanish America. Moriscos became not simply individuals struggling to join a community that was increasingly hostile to them but also symbols that sparked authorities' fears about maintaining religious purity in the face of territorial expansion. Cook reveals how Morisco emigrants shined a light on the complicated question of what it meant to be Spanish in the New World.