Although the term "encyclical" originally simply meant a circulating letter, it acquired a more specific meaning within the context of the Catholic Church. In 1740,
Pope Benedict XIV wrote a letter titled
Ubi primum, which is generally regarded as the first encyclical. The term is now used almost exclusively for a kind of letter sent out by the pope. Papal encyclicals usually take the form of a
papal brief because of their more personal nature as opposed to the formal
papal bull. Like most papal documents the title of the encyclical is usually taken from its
first few words (its
incipit). They are usually written in
Latin unless particularly addressed to the Bishops or the church of one region. Papal encyclicals not in Latin include the 1931 Italian
Non abbiamo bisogno against Italian fascist suppression of groups like
Catholic Action, and the 1937 German
Mit brennender Sorge against the Nazi idolization of race and nation.
Papal use In the encyclical
Humani generis,
Pope Pius XII held that papal encyclicals, even when they are of ordinary
magisterium, can nonetheless be sufficiently authoritative to end theological debate on a particular question: As part of
Catholic social teaching, popes have issued at least 19 encyclicals, over more than a century. On social issues and workers rights,
Pope Leo XIII promulgated the encyclical
Rerum novarum (1891), which was followed by
Quadragesimo anno (1931) of
Pius XI and
Centesimus annus (1991) of
John Paul II.
Pope Pius XII issued ten encyclicals, mostly after 1945, three of them protesting against the
Soviet invasion of
Hungary which suppressed the
Hungarian Revolution in 1956:
Datis nuperrime,
Laetamur admodum and
Luctuosissimi eventus.
Pope Paul VI published an encyclical
Humanae vitae on the topic of
birth control and
euthanasia. ==Anglican usage==