encyclical

encyclical, pastoral letter written by the pope for the whole Roman Catholic Church on matters of doctrine, morals, or discipline. The term derives from the Greek enkyklios, meaning “circular.” Encyclicals are normally addressed to the bishops of the Roman Catholic Church, but a few—notably Pacem in terris (Latin: “Peace on Earth”) by John XXIII in 1963—have been addressed also to “the entire Catholic World” and to “all Men of Good Will.” The formal title of an encyclical consists of the first few words of the official text; the language is usually Latin, and the document is not considered to be infallible. Encyclicals of the late 20th and early 21st centuries are typically translated into many languages and posted on the Holy See’s official website.

Although formal papal letters were issued from the earliest days of the church, the first letter commonly called an encyclical was Ubi primum (“When It First”), dealing with episcopal duties, published by Benedict XIV in 1740. Only from the time of Pius IX (reigned 1846–78) have encyclicals been frequently used to communicate church teaching.

Some encyclicals have stirred much controversy. Notably, Paul VI’s Humanae vitae (“Of Human Life”), issued in 1968 a few years after the sweeping modernizations introduced by the Second Vatican Council (1962–65), firmly rejected the use of artificial contraception. It became one of the church’s most ignored teachings, and many Catholics (including some theologians and bishops) felt it made basic theological mistakes in its reasoning.

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Social encyclicals

In 1891 Leo XIII issued Rerum novarum (“Of New Things”), an encyclical that enunciates the late-19th-century church’s position on social justice, especially in relation to the economic problems created by the Industrial Revolution. It laid the foundation for modern Roman Catholic social teaching and was the first “social encyclical”—that is, one that addresses specific and current moral issues. Many subsequent popes have released social encyclicals. A famous social encyclical of the 21st century is Pope Francis’s Laudato si’ (“Praise Be to You”; 2015), which addresses the environment and treats care for the Earth as a moral issue of urgent concern. The first encyclical of Leo XIV’s papacy was Magnifica humanitas (“Magnificent Humanity”; 2026), which offers moral guidance on the use of artificial intelligence.

The following is a list of all social encyclicals since the late 19th century.

• Rerum novarum (“Of New Things”) by Leo XIII, 1891
• Quadragesimo anno (“In the 40th Year”) by Pius XI, 1931
• Mater et magistra (“Mother and Teacher”) by John XXIII, 1961
• Pacem in terris (“Peace on Earth”) by John XXIII, 1963
• Populorum progressio (“On the Development of Peoples”) by Paul VI, 1967
• Laborem exercens (“On Human Work”) by John Paul II, 1981
• Sollicitudo rei socialis (“On Social Concerns”) by John Paul II, 1987
• Centesimus annus (“In the 100th Year”) by John Paul II, 1991
• Evangelium vitae (“The Gospel of Life”) by John Paul II, 1995
• Deus caritas est (“God Is Love”) by Benedict XVI, 2005
• Caritas in veritate (“Charity in Truth”) by Benedict XVI, 2009
• Laudato si’ (“Praise Be to You”) by Francis, 2015
• Fratelli tutti (“Brothers All”) by Francis, 2020
• Magnifica humanitas (“Magnificent Humanity”) by Leo XIV, 2026