Marrano in the context of "Baruch Spinoza"

Luis de León OESA (Belmonte, Cuenca, 1527 – Madrigal de las Altas Torres, Castile, Spain, 23 August 1591), was a Spanish lyric poet, Augustinian friar, theologian and academic.

While serving as professor of Biblical scholarship at the University of Salamanca, Fray Luis also wrote many immortal works of Spanish Christian poetry and translated both Biblical Hebrew poetry and Latin Christian poetry into the Spanish language. Despite being a devout and believing Roman Catholic priest, Fray Luis was descended from a family of Spanish Jewish Conversos and this, as well as his vocal advocacy for teaching the Hebrew language in Catholic universities and seminaries, drew false accusations from the Dominican Order of the heresies of being both a Marrano and a Judaiser. Fray Luis was accordingly imprisoned for four years by the Spanish Inquisition before he was ruled to be completely innocent of any wrongdoing and released without charge. While the conditions of his imprisonment were never harsh and he was allowed complete access to books, according to legend, Fray Luis started his first post-Inquisition University of Salamanca lecture with the words, "As I was saying the other day..."

Pope Paul IV (Latin: Paulus IV; Italian: Paolo IV; 28 June 1476 – 18 August 1559), born Gian Pietro Carafa, was head of the Catholic Church and ruler of the Papal States from 23 May 1555 to his death, in August 1559. While serving as papal nuncio in Spain, he developed an anti-Spanish outlook that later coloured his papacy. In response to an invasion of part of the Papal States by Spain during his papacy, he called for a French military intervention. After a defeat of the French and with Spanish troops at the edge of Rome, the Papacy and Spain reached a compromise: French and Spanish forces left the Papal States and the Pope thereafter adopted a neutral stance between France and Spain.

Carafa was appointed bishop of Chieti, but resigned in 1524 in order to found with Saint Cajetan the Congregation of Clerics Regular (Theatines). Recalled to Rome, and made Archbishop of Naples, he worked to re-organise the Inquisitorial system in response to the emerging Protestant movement in Europe, any dialogue with which he opposed (the inquisition itself had been first instituted by Pope Innocent III who first regulated inquisitional procedure in the 13th century). Carafa was elected pope in 1555 through the influence of Cardinal Alessandro Farnese in the face of opposition from Charles V, Holy Roman Emperor. His papacy was characterised by strong nationalism in reaction to the influence of Philip II of Spain and the Habsburgs. The appointment of Carlo Carafa as Cardinal Nephew damaged the papacy further, and scandals forced Paul to remove him from office. He curbed some clerical abuses in Rome, but his methods were seen as harsh. He would introduce the first modern Index Librorum Prohibitorum or "Index of Prohibited Books" banning works he saw as in error. In spite of his advanced age, he was a tireless worker and issued new decrees and regulations daily, unrelenting in his determination to keep Protestants and recently immigrated Marranos from gaining influence in the Papal States. Paul IV issued the Papal bull Cum nimis absurdum, which confined Jews in Rome to the neighbourhood claustro degli Ebrei ("enclosure of the Hebrews"), later known as the Roman Ghetto. He died highly unpopular, to the point that his family rushed his burial to make sure his body would not be desecrated by a popular uprising.

New Christian (Latin: Novus Christianus; Spanish: Cristiano Nuevo; Portuguese: Cristão-Novo; Catalan: Cristià Nou; Ladino: Kristiano Muevo; Arabic: المسيحيون الجدد) was a socio-religious designation and legal distinction referring to the population of former Jewish and Muslim converts to Christianity in the Spanish and Portuguese empires, and their respective colonies in the New World. The term was used from the 15th century onwards primarily to describe the descendants of the Sephardic Jews and Moors that were baptized into the Catholic Church following the Alhambra Decree of 1492. The Alhambra Decree, also known as the Edict of Expulsion, was an anti-Jewish law made by the Catholic Monarchs upon the Reconquista of the Iberian Peninsula. It required Jews to convert to Roman Catholicism or be expelled from Spain. Most of the history of the "New Christians" refers to the Jewish converts, who were generally known as Conversos (or in a more derogatory fashion Marranos), while the Muslim converts were called Moriscos.

Because these conversions were achieved in part through coercion and also with the threat of expulsion, especially when it came to the Jews, the Catholic Inquisition and Iberian monarchs suspected a number of the "New Christians" of being crypto-Jews. Subsequently, the Spanish Inquisition and then the Portuguese Inquisition was created to enforce Catholic orthodoxy and to investigate allegations of heresy. This became a political issue in the kingdoms of the Portuguese–Spanish Union itself and their respective empires abroad, particularly in Spanish America, Portuguese America, and the Caribbean. Sometimes "New Christians" travelled to territories controlled by Protestant enemies of Spain, such as the Dutch Empire, the early English Empire, or Huguenot-influenced areas of the Kingdom of France such as Bordeaux, and openly practiced Judaism, which furthered suspicion of Jewish crypsis. Nevertheless, a significant number of those "New Christians" of converso ancestry were deemed by Spanish society as sincerely Catholic and they still managed to attain prominence, whether religious (St. John of the Cross, St. Teresa of Ávila, St. John of Ávila, St. Joseph of Anchieta, Tomás Luis de Victoria, Tomás de Torquemada, Diego Laynez, Francisco de Vitoria, Francisco Suárez, and others) or political (Juan de Oñate, Luis de Carvajal y de la Cueva, Hernán Pérez de Quesada, Luis de Santángel, and others).

Crypto-Judaism is the secret adherence to Judaism while publicly professing to be of another faith; practitioners are referred to as "crypto-Jews" (origin from Greek kryptos – κρυπτός, 'hidden').

The term is especially applied historically to Spanish and Portuguese Jews who outwardly professed Catholicism, also known as Conversos, Marranos, or the Anusim. The phenomenon is especially associated with medieval Spain, following the Massacre of 1391 and the expulsion of the Jews in 1492. After 1492 in Spain and 1497 in Portugal, officially they no longer existed. The Spanish Inquisition and the Portuguese Inquisition were established to monitor converted Jews and Muslims and their descendants for their continued adherence to Christian faith and practice, with severe penalties for those convicted of secretly continuing to practice their original beliefs. This would have involved the Inquisition paying close attention to the households of suspected converted Jews, since most of the families still practicing Judaism would have done so through the food. Information about secretly observant Jews largely survives in Inquisition cases against individuals.