Rerum novarum

Rerum novarum, encyclical issued by Pope Leo XIII in 1891 that laid the foundation for modern Roman Catholic social teaching. Considered by many conservative Catholics to be extremely progressive, Rerum novarum (Latin: “Of New Things”) enunciated the late 19th-century Catholic position on social justice, especially in relation to the problems created by the Industrial Revolution, and it emphasized the church’s right to make pronouncements on social issues as they relate to moral questions. It is also considered the first social encyclical, a pastoral letter that addresses a specific current social issue. Many popes of the 20th and 21st centuries have promulgated encyclicals that expand on the teaching of Rerum novarum.

Impact of the Industrial Revolution

Having begun in Britain in the 18th century, the Industrial Revolution spread to other parts of the world and fundamentally transformed society, introducing new technologies and new ways of living and working. Local economies that had been based on agriculture and handicrafts became dominated by industry and machine manufacturing. Guilds and feudalism gave way to companies and capitalism, and new social classes developed as modes of production sped up and became increasingly specialized. These classes were divided into upper, middle, and working (or lower), according to the type of work performed, income level, and material wealth (including property).

In response to these rapid changes, thinkers became concerned about the effects of industry on society, especially on the working class. Economists and other social scientists developed new ideologies—namely, socialism and communism—that aimed to overthrow capitalism and abolish private property. In 1848 Karl Marx and Friedrich Engels published the pamphlet The Communist Manifesto, which became one of the principal programmatic statements of the European socialist and communist parties in the 19th and early 20th centuries.

One year after The Communist Manifesto was published, Pope Pius IX issued the encyclical Nostis et nobiscum (“You Know as We Do”), which condemned socialism and communism. His response to these ideologies, as well as his approach to the papacy, is important in understanding Leo XIII’s decision to promulgate Rerum novarum more than 40 years later.

Reign of Pius IX: Troubled relations between church and state

Pius IX was a conservative authoritarian who reigned for more than 31 years (1846–78), the longest papacy in history. His accomplishments included defining the doctrine of papal infallibility during the First Vatican Council (1869–70), which Pius had called to respond to what he considered the rising problems of contemporary society and the expectations of the church to modernize.

Pius’s papacy saw other revolutionary changes in the relations between the Roman Catholic Church and European states. In 1870 Italy annexed much of the territory belonging to the Papal States and made Rome (the seat of the church) the Italian capital. To protest this incorporation into a unified Italy, Pius (and several popes thereafter) remained a voluntary “prisoner of the Vatican,” never leaving the small territory of the papal grounds. This situation lasted nearly 60 years. Other hostilities between church and state raged elsewhere. For example, between about 1871 and 1887 the German chancellor Otto von Bismarck waged a bitter struggle, known as Kulturkampf, to subject the Roman Catholic Church in Germany to state controls. Bismarck’s battle was partly a response to Pius’s doctrine of papal infallibility. Among the chancellor’s orders was the exclusion of religious teachers from all state schools in Germany and the suppression of the Jesuits there.

Reign of Leo XIII: A new spirit

Having succeeded Pius IX in 1878, Leo XIII aligned with his predecessor’s vision of the church in some respects: like Pius, he opposed secular liberalism and considered the traditional doctrine of the Christian state as an ideal. But Leo’s papacy ultimately characterized a new spirit.

Are you a student?

Get a special academic rate on Britannica Premium.

Subscribe

Before becoming pope, Leo had served as bishop of the small, obscure diocese of Perugia, Italy, for 32 years, and he had used his ample leisure to read Christian philosophy, particularly that of St. Thomas Aquinas (quoted in five sections of Rerum novarum). From his reading, he became interested in the problem of the relations between the church and modern society, and he was increasingly convinced that church authorities were mistaken in taking a fearful, negative attitude toward the aspirations of the times.

Leo had also served as a papal nuncio (ambassador) in Belgium early in his career, which gave him important skills in diplomacy. After being elected to the papacy, he became known for his diplomatic relations with civil governments, and he concerned himself with renewing the dialogue between the church and the world.

Drafting Rerum novarum: Figures and influences

Several members of Leo’s inner circle were involved in drafting Rerum novarum. The pope worked with Matteo Liberatore, an Italian Jesuit philosopher and founder of the periodical La civiltà cattolica (“Catholic Civilization”); the Italian cardinals Tommaso Maria Zigliara and Camillo Mazzella; and the Italian monsignors Gabriele Boccali (one of Leo’s secretaries) and Alessandro Volpini.

Scholars believe that the document was also influenced by the ideas of several Catholic prelates, theologians, and social reformers who were interested in the rights of workers, including the Bavarian bishop Wilhelm Emmanuel von Ketteler, the English cardinal Henry Edward Manning, the American cardinal James Gibbons, and the French industrialist Léon Harmel. In addition, Liberatore shared with Leo an interest in Thomism (i.e., the theology and philosophy of St. Thomas Aquinas), which informed the main points of Rerum novarum.

Main points of Rerum novarum

Addressed to the bishops of the Roman Catholic Church, Rerum novarum begins with piercing urgency:

That the spirit of revolutionary change, which has long been disturbing the nations of the world, should have passed beyond the sphere of politics and made its influence felt in the cognate sphere of practical economics is not surprising. The elements of the conflict now raging are unmistakable, in the vast expansion of industrial pursuits and the marvellous discoveries of science; in the changed relations between masters and workmen; in the enormous fortunes of some few individuals, and the utter poverty of the masses; the increased self reliance and closer mutual combination of the working classes; as also, finally, in the prevailing moral degeneracy.

Immediately, the document makes clear that the church must have a role in addressing the current conditions of the working class and reconciling different opinions on the matter. However, it cautions, “The danger lies in this, that crafty agitators are intent on making use of these differences of opinion to pervert men’s judgments and to stir up the people to revolt.”

Indeed, a particular concern of Rerum novarum is the threat of socialism, which “must be utterly rejected, since it only injures those whom it would seem meant to benefit, is directly contrary to the natural rights of mankind, and would introduce confusion and disorder into the commonweal.” Drawing from scripture and the writings of Aquinas, Rerum novarum identifies the right of private property as the foundation on which the remedy for the social problems at hand must be based, and yet the document affirms the duties of citizens to uphold the common good, regardless of private wealth:

Private ownership, as we have seen, is the natural right of man, and to exercise that right, especially as members of society, is not only lawful, but absolutely necessary. “It is lawful,” says St. Thomas Aquinas, “for a man to hold private property; and it is also necessary for the carrying on of human existence.” But if the question be asked: How must one’s possessions be used?—the Church replies without hesitation in the words of the same holy Doctor: “Man should not consider his material possessions as his own, but as common to all, so as to share them without hesitation when others are in need. Whence the Apostle [St. Paul] with, ‘Command the rich of this world…to offer with no stint, to apportion largely [1 Timothy 6:17–18].’ ”

The main points of Rerum novarum are

• the necessity of private property, which the document upholds as a natural right
• the dignity of labor and workers
• the mutual responsibilities of employers and workers, including workers’ right to a fair wage and their duty to respect their employers’ property
• the right of workers to organize and form unions
• the state’s role in protecting the rights of all citizens, especially the poor and vulnerable, and in ensuring workers a living wage and tolerable working conditions
• the church’s role in recognizing societal changes, serving as a moral authority, and caring for the poor
• the false solution offered by socialism
• the necessity of collaboration to achieve and maintain social harmony

Rerum novarum sees collaboration between workers and employers and between church and state as the solution to the problems of the Industrial Revolution. The church’s role is paramount: “There is no intermediary more powerful than religion (whereof the Church is the interpreter and guardian) in drawing the rich and the working class together, by reminding each of its duties to the other, and especially of the obligations of justice.”

The encyclical ends with another appeal to the bishops, that “they should never cease to urge upon men of every class, upon the high-placed as well as the lowly, the Gospel doctrines of Christian life; by every means in their power they must strive to secure the good of the people.”

Influence on church teaching of the 20th and 21st centuries

Rerum novarum is often cited as the foundational document of Catholic social teaching. In a 2004 compendium of the church’s social doctrine, the Vatican wrote, “Grafting itself onto a tradition hundreds of years old, [Rerum novarum] signals a new beginning and a singular development of the Church’s teaching in the area of social matters.”

Most popes since Leo XIII have promulgated social encyclicals that refer back to Rerum novarum and expand on its teaching by addressing other contemporary issues. These issues include nuclear proliferation (John XXIII’s Pacem in terris, or “Peace on Earth,” in 1963); abortion, capital punishment, and euthanasia (John Paul II’s Evangelium vitae, or “The Gospel of Life,” in 1995); poverty and globalization (Benedict XVI’s Caritas in veritate, or “Charity in Truth,” in 2009); and environmentalism and climate change (Francis’s Laudato si’, or “Praise Be to You,” in 2015). A few popes have also issued encyclicals to commemorate a significant anniversary of Rerum novarum, beginning with Pius XI’s Quadragesimo anno (“In the 40th Year”) in 1931. For a full list of the social encyclicals of the Roman Catholic Church, see encyclical: Social encyclicals.

Pope Leo XIV and Rerum novarum

In May 2025 Robert Prevost, a cardinal born in the United States and the former head of the global Augustinian order, was elected pope. Having chosen Leo XIV as his papal name, in honor of Leo XIII, the new pope cited Rerum novarum as an important influence on his choice of name. Specifically, he drew a connection between the 1891 document’s teaching on labor and the rights of workers on one hand and the rise of artificial intelligence in the 21st century on the other, which some people view as a threat to humanity:

In our own day, the Church offers to everyone the treasury of her social teaching in response to another industrial revolution and to developments in the field of artificial intelligence that pose new challenges for the defence of human dignity, justice and labour.