Encyclical (Lat. Litteræ Encyclicæ).—According to its etymology, an encyclical (from the Greek ἐγκύκλιος, κὐκλος meaning a circle) is nothing more than a circular letter. In modern times, usage has confined the term almost exclusively to certain papal documents which differ in their technical form from the ordinary style of either Bulls or Briefs, and which in their superscription are explicitly addressed to the patriarchs, primates, archbishops, and bishops of the Universal Church in communion with the Apostolic See. By exception, encyclicals are also sometimes addressed to the archbishops and bishops of a particular country. Thus this name is given to the letter of Pius X (January 6, 1907) to the bishops of France, in spite of the fact that it was published, not in Latin, but in French; while, on the other hand, the letter "Longinqua Oceani" (January 5, 1895) addressed by Leo XIII to the archbishops and bishops of the United States, is not styled an encyclical, although in all other respects it exactly observes the forms of one. From this and a number of similar facts we may probably infer that the precise designation used is not intended to be of any great significance. From the nature of the case encyclicals addressed to the bishops of the world are generally concerned with matters which affect the welfare of the Church at large. They condemn some prevalent form of error, point out dangers which threaten faith or morals, exhort the faithful to constancy, or prescribe remedies for evils foreseen or already existent. Inform an encyclical at the present day begins thus—we may take the encyclical "Pascendi" on Modernism as a specimen:
"Sanctissimi Domini Nostri Pii Divinae, Providentiae Papae X Litterae Encyclicae ad Patriarchas, Primates, Archiepiscopos, Episcopos aliosque locorum Ordinarios pacem et communionem cum Apostolicae Sede habentes de Modernistarum Doctrinis. Ad Patriarchas, Primates, Archiepiscopos, Episcopos aliosque locorum Ordinarios, pacem et communionem cum Apostolicae Sede habentes, Pius PP. X., Venerabiles Fratres, saluted et apostolicam benedictionem. Pascendi dominici gregis mandatum", etc.
The conclusion takes the following form: Nos vero, pignus caritatis Nostrae divinique in adversis solatii, Apostolicam Benedictionem vobis, cleris, populisque vestris amantissime impertimus. Datum Romae, apud Sanctum Petrum, die VIII Septembris MCMVII, Pontificatus Nostri anno quinto. Pius PP. X."
Although it is only during the last three pontificates that the most important utterances of the Holy See have been given to the world in the shape of encyclicals, this form of Apostolic Letter has long been in occasional use. Almost the first document published by Benedict XIV after his election was an "Epistola encyclica et commonitoria" on the duties of the episcopal office (December 3, 1740). Under Pius IX many momentous utterances were presented in this shape. The famous pronouncement "Quanta cura" (December 8, 1864), which was accompanied by a Syllabus (q.v.) of eighty anathematized errors, was an encyclical. Another important encyclical of Pius IX, described as an "Encyclical of the Holy Office", was that beginning "Supremae" (August 4, 1856) in condemnation of Spiritualism. Leo XIII published a series of encyclicals on social and other questions which attracted universal attention. We may mention especially "Inscrutabilis" (April 21, 1878) on the evils of modern society; "Aeterni Patris" (August 4, 1879) on St. Thomas Aquinas and Scholastic philosophy; "Arcanum divinae sapientiae" (February 10, 1880) on Christian marriage and family life; "Diuturnum illud" (June 29, 1881) on the origin of civil authority; "Immortale Dei" (November 1, 1885) on the Christian constitution of states; "Libertas praestantissimum" (June 20, 1888) on true liberty; "Rerum novarum" (May 16, 1891) on the labor question; "Providentissimus Deus" (November 18, 1893) on Holy Scripture; "Satis cognitum" (June 29, 1896) on religious unity. Pius X has shown the same favor for this form of document, e.g. in his earnest commendation of catechetical instruction "Acerbo nimis" (April 15, 1906) his address on the centenary of St. Gregory the Great (March 12, 1904), his first letter to the clergy and faithful of France, "Vehementer nos" (February 11, 1906), his instructions on intervention in politics to the people of Italy, and in the pronouncement on Modernism already mentioned.