In this study, Anne Marie Wolf focuses on the thought of Juan de Segovia, a fifteenth-century Castilian university professor who participated in the Council of Basel and later worked with a Muslim scholar to produce a Latin translation of the Qur'an. Juan opposed armed crusade against the Turks as a response to the fall of Constantinople in 1453. While he may have thought crusading was a bad idea, he was not disposed to allow Muslims to continue in their beliefs—his goal was the conversion of all Muslims, and he thought armed conflict was antithetical to that goal (killing Muslims seemed to make them entrenched enemies unlikely to listen to the word of God or be convinced to convert). Wolf argues that Juan's experience as a Spaniard and as professor of theology at the University of Salamanca, along with his role as a participant in the Council of Basel in the first decades of the fifteenth century, shaped his attitude toward Muslims as rational beings capable of being converted peaceably to Christianity. These attitudes later manifested in his project to translate the Qur'an into Latin, discussed at length in letters he exchanged with European intellectuals such as Nicholas de Cusa and Jean Germain.

Wolf bases her study on Juan's lectures and correspondence available in manuscript in Spanish archives and the Vatican Library, previous studies on Juan de Segovia and his Qu'ran translation (including Darío Cabanelas Rodríguez, Juan de Segovia y el problema islámico [Universidad de Madrid, 1952]; Jesse Mann, “The Historian and the Truths: Juan de Segovia's Explanatio de tribus veritatibus fidei,” PhD diss. [University of Chicago, 1993]; Gerard Weigers, Islamic Literature in Spanish and Aljamiado: Yça of Segovia [Brill, 1994]; and Thomas Burman, Reading the Qur'an in Latin Christendom [University of Pennsylvania Press, 2007]), as well as on scholarship on the Council of Basel and fifteenth-century humanism (including Antony Black, Council and Commune: The Conciliar Movement and the Fifteenth-Century Heritage [Patmos, 1979]; and Nancy Bisaha, Creating East and West: Renaissance Humanists and the Ottoman Turks [University of Pennsylvania Press, 2003]).

In chapters 1 and 2, Wolf explores what elements of Juan's experiences as a professor at the University of Salamanca, and then as diplomat for the Crown of Castile, would later contribute to his attitude toward Muslims. In the first chapter, Wolf explores the rising power and fortunes of the University of Salamanca, where Juan trained and spent the first twenty-odd years of his career. As part of an insecure Kingdom of Castile, the university and its faculty and students witnessed and participated in the various power and ideological struggles that plagued the kingdom, including the struggle between Juan II and the church, as well as the struggles within the church. In the second chapter, Wolf briefly presents some of what we know about the Muslim populations of Castile and Aragón in the thirteenth, fourteenth, and fifteenth centuries. She reviews Cabanelas Rodríguez's discovery of two encounters Juan had with “real Muslims” before his famous engagement of the Morisco faqih, Yça Gidelli, as translator of the Qur'an. The first was an attempt in 1431 to engage in theological debate with an emissary of Yusuf IV, emir of Granada. According to a letter Juan sent years later to Jean Germain, Yusuf refused, saying no qualified learned Muslim could be found to participate in such debate. Juan was more successful on a trip to Medina del Campo, finding a Granadan ambassador willing to engage in a theological discussion with him. Based on these two documented cases, to which Wolf repeatedly refers in the present study, she concludes that, as a Castilian, Juan must have had contact with “real” Muslims.

In chapters 3 and 4, Wolf explores how the ideas and policies discussed at the Council of Basel (1431–1445), as well as the people with whom Juan established relationships at the Council, later shaped his philosophy toward Muslims. As Wolf shows in chapter 3, Juan was an active participant in the Council and consistently supported the conciliarist positions against the pope. Wolf argues that Juan was deeply impressed by the Council's dealings with the Hussites and the latter's peaceable reconciliation with the church, arguing that this successful and peaceful reincorporation of believers into the church became the model for how he imagined the church should deal with Muslims. In chapter 4, Wolf shows how Juan's position vis-à-vis the Muslims after 1453 differed from that of his contemporaries—many of whom had been friends and acquaintances from the Council of Basel. Wolf shows that Juan's opinion in favor of peace put him at odds with fifteenth-century humanists and clerics such as Enea Silvio Picolominni (future Pope Pius II), Jean Germaine, and Cardinal Cervantes, who advocated armed crusade against the Muslims.

In chapter 5, Wolf reviews Juan's three-part plan for establishing peace with Muslims and eventually converting them to Christianity, outlined in his letters to Nicholas of Cusa. This plan involved several stages that progressed from an initial meeting or summit of learned representatives of both Western Christian and Muslim leaders and culminated in the peaceful debate of theological differences. This plan reflected, in Juan's opinion, the initial teaching of Jesus, who evangelized “near and far” (177). In this chapter, Wolf also provides more details about the man Juan contracted to translate the Qur'an into Castilian (from which Juan made his Latin translation), Yça Gidelli, a religious authority and community leader from the Muslim community of Segovia. Wolf includes in the indices (232–261) the Latin and facing-page English translations of Juan's speeches to the University of Salamanca, Repetitio de fide catholica, De mittendo gladio divini Spiritusin corda sarracenorum, and his letter to Nicholas de Cusa from 1454.

Wolf convincingly shows that Juan de Segovia—a Castilian intellectual who worked with a Morisco intellectual to translate the Qur'an and who argued for the peaceful conversion of Muslims as well as for shared government within the church (and de facto the curbing of papal authority) even after the fall of Constantinople—merits more critical attention. This study of Juan's life and works adds to a growing body of scholarship on aspects of Europe's relationship with Islam in the early modern period. In addition, Wolf's focus on the centrality of the Qur'an and sacred texts in Juan's thought compliments Burman's Reading the Qur'an in Latin Christendom. Juan's faith and intellectual interest in religious conversion (and the role of debate and sacred texts in it) provides yet another Iberian example of this complex cultural phenomenon as explored by Ryan Szpiech (Narratives of Conversion [University of Pennsylvania Press, 2012]). Wolf's comparison of Juan and Nicholas de Cusa's advocation of peace with Muslims expands the still relatively small number of studies (in comparison with the voluminous scholarship on the Crusades) on non-military alternatives to the war advocated by most of Juan's contemporaries. This study of Juan's thought and collaboration with the Morisco intellectual Yça Gidelli will be of interest to scholars of European history and culture, early modern church and Islamic history, Renaissance humanism, aljamiado literature, and religious studies.