Index Librorum Prohibitorum in the context of "Book censorship"

The Spirit of Law (French: De l'esprit des lois, originally spelled De l'esprit des loix), also known in English as The Spirit of [the] Laws, is a treatise on political theory, as well as a pioneering work in comparative law by Montesquieu, published in 1748. Originally published anonymously, as was the norm, its influence outside France was aided by its rapid translation into other languages. In 1750 Thomas Nugent published an English translation, many times revised and reprinted in countless editions. In 1751 the Roman Catholic Church added De l'esprit des lois to its Index Librorum Prohibitorum ("List of Prohibited Books").

Montesquieu's treatise, already widely disseminated, had an enormous influence on the work of many others, most notably: Catherine the Great, who produced Nakaz (Instruction); the Founding Fathers of the United States Constitution; and Alexis de Tocqueville, who applied Montesquieu's methods to a study of American society, in Democracy in America. British historian and politician Macaulay referenced Montesquieu's continuing importance when he wrote in his 1827 essay entitled "Machiavelli" that "Montesquieu enjoys, perhaps, a wider celebrity than any political writer of modern Europe" [1].

Emile, or On Education (French: Émile, ou De l’éducation) is a treatise on the nature of education and on the nature of man written by Jean-Jacques Rousseau, who considered it to be the "best and most important" of all his writings. Due to a section of the book entitled "Profession of Faith of the Savoyard Vicar", Emile was banned in Paris and Geneva and was publicly burned in 1762, the year of its first publication. It was forbidden by the Church being listed on the Index Librorum Prohibitorum. During the French Revolution, Emile served as the inspiration for what became a new national system of education. After the American Revolution, Noah Webster used content from Emile in his best-selling schoolbooks and he also used it to argue for the civic necessity of broad-based female education.

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.

Dialogue Concerning the Two Chief World Systems (Dialogo sopra i due massimi sistemi del mondo) is a 1632 book by Galileo Galilei comparing Nicolaus Copernicus's heliocentric system model with Ptolemy's geocentric model. Written in Italian, it was translated into Latin as Systema cosmicum (Cosmic System) in 1635 by Matthias Bernegger. The book was dedicated to Galileo's patron, Ferdinando II de' Medici, Grand Duke of Tuscany, who received the first printed copy on February 22, 1632. It consists of four Socratic dialogues between the Copernican Salviati, the educated layman Sagredo and the geocentrist Simplicio. They discuss the findings of their "mutual friend the Academician" (Galileo).

In the heliocentric system, the Earth and other planets orbit the Sun, while in the Ptolemaic system, everything in the Universe circles around the Earth. The Dialogue was published in Florence under a formal license from the Inquisition. In 1633, Galileo was found to be "vehemently suspect of heresy" based on the book, which was then placed on the Index of Forbidden Books, from which it was not removed until 1835 (after the theories it discussed had been permitted in print in 1822). In an action that was not announced at the time, the publication of anything else he had written or ever might write was also banned in Catholic countries.