In The Fortress of Faith: The Attitudes Towards Muslims in Fifteenth Century Spain, Ana Echevarría presents a study of four mid-15th-century texts and argues that their polemical tone toward the Muslim world was inspired by contemporary historical events and revealed a Christian Spain preparing itself to end Muslim rule on the Iberian Peninsula. She argues that the events of 1450–70 are key to understanding Fernando and Isabel's renewed march against Granada in 1474 and that ecclesiastical literature of this time—as a manifestation of a “frontier church”—can provide a glimpse of the ideas common at court and among the clergy. At the center of her book are the works of three theologians (Juan de Segovia, Alonso de Espina, and Juan de Torquemada) and one layman (the Aragonese Pedro de Cavallería)—all written between 1450 and 1461—and Echevarría juxtaposes these texts with a wide selection of similar treatises written in Spain and elsewhere since the Muslim invasion of Iberia in 711. For each of her four primary texts, she provides the historical context of the author's life as well as an analysis of each work's style, sources, symbolism, and mode of argumentation against Islam (which, in general, involved allegations about the illegitimacy of the Muslim Prophet, holy text, or tenets). She then compares the views of these authors with the legal norms governing interactions among Muslims, Christians, and Jews in 15th-century Spain and concludes that both reveal an “evolution towards intolerance and violence which was common to the society and its rulers” and that impelled the eventually successful conquest of Granada.