Pope John XXIII (1881-1963, r. 1958-1963) issued eight papal encyclicals during his five-year reign as pope of the Catholic Church. An encyclical is a letter issued by the pope that is usually addressed to Catholic bishops or laity in a particular area or of the whole world. Encyclicals may condemn errors, point out threats to faith and morals, exhort faithful practices or provide remedies for present and future dangers to the church. The authority of the encyclical varies depending on the circumstances on the content and is not necessarily infallible. The title of an encyclical is usually taken from its incipit (its first few words). Two of his encyclicals, Mater et magistra and Pacem in terris, are especially important.
John XXIII's first encyclical, Ad Petri Cathedram, was issued eight months into his pontificate and was neither an important social document nor doctrinal exposition. Instead it looked at truth, unity and peace with distinctive familiarity and concern. The second, Sacerdotii nostri primordia, commemorated the 100th anniversary of the death of St. John Vianney, while Grata recordatio considered the use of the Rosary. Princeps pastorum, his fourth encyclical, used 1 Peter 5:4 as its biblical text and celebrated Catholic missions.
Mater et magistra, the fifth encyclical, carried forward ideas from Leo XIII's Rerum novarum (1891), which had been issued 70 years prior, as well as from Pius XI's Quadragesimo anno (1931). It considers social ethics with its most important point being the application of natural law to the international community. It is one of the longest encyclicals, at more than 25,000 words. The sixth encyclical, Aeterna Dei sapientia, commemorated the death of Pope Leo I and called for unity within Christendom from external movements such as communism and secularism. The penultimate encyclical, Paenitentiam agere, considered penance and the then-upcoming Second Vatican Council. John XXIII's final encyclical, Pacem in terris, was written two months before his death. It is long – at over 15,000 words – and was the first in history to have been addressed to "all men of good will", rather than only the clergy and laity of the church. It was hailed as "one of the most profound and significant documents of our age".
|No.||Latin title||English translation||Subject||Date||Text|
|1||Ad Petri Cathedram||To the Chair of Peter||On truth, unity and peace in a spirit of charity|
|2||Sacerdotii nostri primordia||From the Beginning of Our Priesthood||On St. John Vianney|
|3||Grata recordatio||With Joyful Recollection||On the Rosary: prayer for the church, missions, international and social problems|
|4||Princeps pastorum||The Prince of the Shepherds||On the missions, native clergy and lay participation|
|5||Mater et magistra||Mother and Teacher||On Christianity and social progress|
|6||Aeterna Dei sapientia||God's Eternal Wisdom||On commemorating the fifteenth centennial of the death of Pope St. Leo I|
|7||Paenitentiam agere||Penance for Sins||On the need for the practice of interior and exterior penance|
|8||Pacem in terris||Peace on Earth||On establishing universal peace in truth, justice, charity and liberty|
The significant new thrust in the encyclical is its application of natural law theory to the international community, and its recognition that in our new and complex society there will be more occasions than in the past in which activities formerly conducted by private individuals will have to be administered by the state.