The Catholic Church, also known as the Roman Catholic Church, is the world's largest Christian church, with over a billion members world wide. Its spiritual head is the Pope, who it teaches is the successor of St Peter with a universal primacy. The Church sees its mission as spreading the gospel of Christ, administering its sacraments and exercising charity.
The Catholic Church is one of the oldest religious institutions in the world and has played a prominent role in the history of Western civilisation. It teaches that its bishops are successors of Christ's apostles and that by guidance of the Holy Spirit it can define its dogmatic doctrines infallibly.
The Greek word καθολικός (katholikos) means "universal" or "general", and is equivalent to καθόλου (katholou), a contraction of the phrase κατὰ ὅλου (kata holou), "according to the whole". The word was first used to describe the Church in the early 2nd century. Since the East-West Schism of 1054, the churches that remained in communion with the See of Rome (the diocese of Rome and its bishop, the Pope, the primal patriarch) have been known as "Catholic", while the Eastern churches that rejected the pope's authority have generally been known as "Orthodox" or "Eastern Orthodox". Following the Reformation in the 16th century, the Church "in communion with the Bishop of Rome" used the term "Catholic" to distinguish itself from the various Protestant churches that split off. The name "Catholic Church" appears in the title of the Catechism of the Catholic Church. It is also the term that Paul VI used when signing the sixteen documents of the Second Vatican Council. Church documents both of the Holy See and of certain episcopal conferences occasionally refer to the Church by the name "Roman Catholic Church". In the Catechism of Pope Pius X the Church is called "Roman".
Conditions in the Roman Empire facilitated the spread of new ideas,=""bokenkotter24"/>" note="note"/> and Jesus's apostles gained converts in Jewish communities around the Mediterranean Sea. As preachers such as Paul of Tarsus began converting Gentiles, Christianity grew away from Jewish practices and established itself as a separate religion.
The early Church was more loosely organized and based on evangelism, at times resulting in diverse interpretations of Christian beliefs. In part to ensure a greater consistency in their teachings, by the early 2nd century, Christian communities had adopted a more structured hierarchy, with a central 'bishop' having authority over the clergy in his city. The organization of dioceses was established mirroring the territories and cities of the Roman Empire. Bishops in politically important cities exerted greater authority over bishops in nearby cities. The churches in Antioch, Alexandria, and Rome held the highest positions, but sees considered "apostolic" retained certain rights of governance and discipline over the other sees "because of their superior origin". By at least the 3rd century, the Roman bishop already functioned as a court of appeals for problems that other bishops could not resolve. Beginning in the 2nd century, bishops often congregated in regional synods to resolve doctrinal and policy issues. Doctrine was further refined by a series of influential theologians and teachers, known collectively as the Church Fathers. Ecumenical councils came to be recognized[who?] as infallible and authoritative in resolving theological disputes.
Unlike most religions in the Roman Empire, Christianity required its adherents to renounce all other gods. Christians' refusal to join pagan celebrations meant they were unable to participate in much of public life. This refusal caused non-Christians to fear that the Christians were angering the gods. Christian secrecy about their rituals spawned rumours that Christians were orgiastic, incestuous, atheistic cannibals. Local officials sometimes saw Christians as troublemakers and sporadically persecuted them. A series of more centrally organized persecutions of Christians emerged in the late 3rd century, when emperors decreed that the Empire's military, political, and economic crises were caused by angry gods. All residents were ordered to give sacrifices or be punished. Relatively few Christians were executed, His figures are not complete, but have been used to estimate the total number of martyrs across the empire. others were imprisoned, tortured, put to forced labor, castrated, or sent to brothels; others fled or managed to go undetected, and some renounced their beliefs. Disagreements over what role, if any, these apostates should have in the Catholic Church led to the Donatist and Novatianist schisms.