Catholic Church

The First Ecumenical Council of the Vatican, commonly known as the First Vatican Council or Vatican I, was the 20th ecumenical council of the Catholic Church, held three centuries after the preceding Council of Trent which was adjourned in 1563. The council was convoked by Pope Pius IX on 29 June 1868, under the rising threat of the Kingdom of Italy encroaching on the Papal States. It opened on 8 December 1869 and was adjourned on 20 September 1870 after the Italian Capture of Rome. Its best-known decision is its definition of papal infallibility.

The council's main purpose was to clarify Catholic doctrine in response to the rising influence of the modern philosophical trends of the 19th century. In the Dogmatic Constitution on the Catholic Faith (Dei Filius), the council condemned what it considered the errors of rationalism, anarchism, communism, socialism, liberalism, materialism, modernism, naturalism, pantheism, and secularism.

Pope Boniface VIII (Latin: Bonifacius PP. VIII, Italian: Bonifacio VIII; born Benedetto Caetani; c. 1230 – 11 October 1303) was head of the Catholic Church and ruler of the Papal States from 24 December 1294 until his death in 1303. The Caetani family was of baronial origin with connections to the papacy. He succeeded Pope Celestine V, who had abdicated from the papal throne. Boniface spent his early pontificate abroad in diplomatic roles.

Boniface VIII put forward some of the strongest claims of any pope to temporal as well as spiritual power. He involved himself often with foreign affairs, including in France, Sicily, Italy, and the First War of Scottish Independence. These views, and his chronic intervention in temporal affairs, led to many bitter quarrels with Albert I of Germany, Philip IV of France, and Dante Alighieri, who expected the pope to soon arrive at the eighth circle of Hell in his Divine Comedy, among the simoniacs.

Decretals (Latin: litterae decretales) are letters of a pope that formulate decisions in ecclesiastical law of the Catholic Church.

They are generally given in answer to consultations but are sometimes given due to the initiative of the pope himself. These furnish, with the canons of the councils, the chief source of the legislation of the church, and formed the greater part of the Corpus Iuris Canonici before they were formally replaced by the Codex Iuris Canonici of 1917. However, Cardinal Pietro Gasparri led the papal commission for the revision of canon law and later on published a guide to the fontes (sources) used in the 1917 code. Many canons in this code can easily be retraced in their relationship to and dependency on medieval decretals as well as Roman law.

This chronological list of the popes of the Catholic Church corresponds to that given in the Annuario Pontificio under the heading "I Sommi Pontefici Romani" (The Roman Supreme Pontiffs), excluding those that are explicitly indicated as antipopes. Published every year by the Roman Curia, the Annuario Pontificio no longer identifies popes by regnal number, stating that it is impossible to decide which pope represented the legitimate succession at various times. The 2001 edition of the Annuario Pontificio introduced "almost 200 corrections to its existing biographies of the popes, from St Peter to John Paul II". The corrections concerned dates, especially in the first two centuries, birthplaces and the family name of one pope.

The term pope (Latin: papa, lit. 'father') is used in several churches to denote their high spiritual leaders (for example Coptic pope). This title is usually used in English to refer to the head of the Catholic Church. The Catholic pope uses various titles by tradition, including Summus Pontifex, Pontifex Maximus, and Servus servorum Dei. Each title has been added by unique historical events, and unlike other papal prerogatives, is not incapable of modification.

Catholic theology is the understanding of Catholic doctrine or teachings, and results from the studies of theologians. It is based on canonical scripture, and sacred tradition, as interpreted authoritatively by the magisterium of the Catholic Church. This article serves as an introduction to various topics in Catholic theology, with links to where fuller coverage is found.

Major teachings of the Catholic Church discussed in the early councils of the church are summarized in various creeds, especially the Nicene (Nicene-Constantinopolitan) Creed and the Apostles' Creed. Since the 16th century the church has produced catechisms which summarize its teachings; in 1992, the Catholic Church published the official Catechism of the Catholic Church.

Papal infallibility is a dogma of the Catholic Church (both the Latin and Eastern Catholic churches) which states that, in virtue of the promise of Jesus to Peter, the Pope when he speaks ex cathedra is preserved from the possibility of error on doctrine "initially given to the apostolic Church and handed down in Scripture and tradition". It does not mean that the pope cannot sin or otherwise err in many cases. This doctrine, defined dogmatically at the First Vatican Council of 1869–1870 in the document Pastor aeternus, is claimed to have existed in medieval theology and to have been the majority opinion at the time of the Counter-Reformation.

The doctrine of infallibility relies on one of the cornerstones of Catholic dogma, that of papal supremacy, whereby the authority of the pope is the ruling agent as to what are accepted as formal beliefs in the Catholic Church. The use of this power is referred to as speaking ex cathedra. "Any doctrine 'of faith or morals' issued by the pope in his capacity as successor to St. Peter, speaking as pastor and teacher of the Church Universal [Ecclesia Catholica], from the seat of his episcopal authority in Rome, and meant to be believed 'by the universal church,' has the special status of an ex cathedra statement. Vatican Council I in 1870 declared that any such ex cathedra doctrines have the character of infallibility (session 4, Constitution on the Church 4)."

Pope Martin V (Latin: Martinus V; Italian: Martino V; January/February 1369 – 20 February 1431), born Oddone Colonna, was the head of the Catholic Church and ruler of the Papal States from 11 November 1417 to his death in February 1431. His election effectively ended the Western Schism of 1378–1417. As of 2025, he remains the last pope to have taken the pontifical name "Martin".

Peter of Candia, also known as Peter Phillarges (Greek: Πέτρος Φιλάργης) (c. 1339 – 3 May 1410), denominated Alexander V (Latin: Alexander PP.V; Italian: Alessandro V), was an antipope elected by the Council of Pisa during the Western Schism (1378–1417). He invalidly reigned briefly from 26 June 1409 to his death in 1410, in opposition to the true Roman Pope Gregory XII and the Avignon antipope Benedict XIII. In the 20th century, the Catholic Church reinterpreted the Western Schism by recognising the Roman Popes of the period as legitimate. The pontificate of Gregory XII was thus recognized to extend to 1415, and Alexander V was and is now recognized as an antipope.

The Catechism of the Catholic Church (Latin: Catechismus Catholicae Ecclesiae; commonly called the Catechism or the CCC) is a reference work that summarizes the Catholic Church's doctrine. It was promulgated by Pope John Paul II in 1992 as a reference for the development of local catechisms, directed primarily to those (in the church) responsible for catechesis and offered as "useful reading for all other Christian faithful". It has been translated into and published in more than twenty languages worldwide.

John Paul II referred to it as "the Catechism of the Second Vatican Council", and Pope Benedict XVI described it as "one of the most important fruits of the Second Vatican Council".

Mass is the main Eucharistic liturgical service in many forms of Western Christianity. The term Mass is commonly used in the Catholic Church, Western Rite Orthodoxy, Old Catholicism, and Independent Catholicism. The term is also used in many Lutheran churches, as well as in some Anglican churches, and on rare occasion by other Protestant churches.

Other Christian denominations may employ terms such as Divine Service or worship service (and often just "service"), rather than the word Mass. For the celebration of the Eucharist in Eastern Christianity, including Eastern Catholic Churches, other terms such as Divine Liturgy, Holy Qurbana, Holy Qurobo and Badarak (or Patarag) are typically used instead.