Answer
The Roman Catholic Church teaches that it began when the Holy Spirit descended on the day of Pentecost, fifty days after Jesus ascended into heaven (Acts 1:8; 2:1–13). Yet many of the doctrines that define Catholicism developed much later. For example, the office of the pope, the practice of praying the rosary, and doctrines like transubstantiation—the belief that the bread and cup of the Lord’s Supper change into the body and blood of Christ—emerged in subsequent centuries. For this reason, we do not place the beginning of the Roman Catholic Church at Pentecost. Rather, we would equate the beginning of Catholicism with Constantine’s Edict of Milan in AD 313 or Pope Gregory I’s consolidation of lands under his authority in 590.
Over its history, the Catholic Church has experienced four distinct eras: the Early Church (fourth to fifth centuries), the Middle Ages (fifth to fifteenth centuries), the Reformation and Counter-Reformation (sixteenth to seventeenth centuries), and the Contemporary (eighteenth to twenty-first centuries).
In the Early Church era (fourth to fifth centuries), three notable developments were overcoming persecution, articulating doctrine, and the legalization of Christianity. First, Christians faced severe persecution, as they were accused of sacrilege like blasphemy and crimes like treason. Second, the Church articulated its core doctrines through creeds, including the Nicene Creed (AD 325), which affirmed biblical teachings like the Trinity. A key theologian in this era was Augustine of Hippo (AD 354—430), whose book, Confessions, significantly impacted the Church. Third, the Roman Emperor Constantine made Christianity legal in AD 313.
Yet another key development in the Early Church era was the emergence of the papacy. Even prior to the Edict of Milan, in the third century AD, Stephen, the bishop of Rome, and Cyprian, the bishop of Carthage, argued about the legitimacy of baptisms performed in heretical congregations. Both men claimed to have the authority to declare a verdict. Stephen, arguing that he had “the keys to the kingdom”—that is, the authority handed down from Peter (see Matthew 16:18–19)—influenced the Church’s eventual stance on the matter. This event played an important role in the Church’s gradual recognition of the bishop in Rome as the successor to Peter’s apostolic authority. Later, in the sixth century, Gregory the Great applied the title “pope” to the bishop of Rome.
During the Middle Ages (fifth to fifteenth centuries), the Catholic Church witnessed the rise of the monastic movement and experienced internal and external threats. Early monasticism played a key role in evangelization, with missionaries like Patrick spreading Christianity to Ireland in the fifth century. Additionally, the Church faced external threats from Vikings and Muslims. It also dealt with internal challenges from political and theological divisions. These resulted in the Great Schism in AD 1054 when the Eastern Orthodox Church and the Roman Catholic Church officially separated. Amid these challenges, a new wave of monasticism gave rise to orders like the Franciscans, Dominicans, and Augustinians.
Theological developments continued during the Middle Ages. A key theologian was Thomas Aquinas (1225—1274), whose influential work Summa Theologica helped shape Catholic theology. Drawing heavily on the philosophy of Aristotle, Aquinas refined the Church’s understanding of transubstantiation, explaining how the bread and cup transform into the body and blood of Jesus. While the doctrine had been established at the Fourth Lateran Council in 1215, the Catholic Church later adopted Aquinas’ explanation for the nature of the Eucharist.
The Reformation and Counter-Reformation era (sixteenth to seventeenth centuries) has its roots in the fourteenth century. At that time, protests emerged within the Church. John Wycliffe (1331—1384) and Jan Hus (1370—1415) criticized the papacy’s embrace of unbiblical practices like selling indulgences—offering forgiveness in exchange for money—to fundraise for the Church. Later, Martin Luther of Germany (1483—1546), Ulrich Zwingli of Switzerland (1484—1531), and John Calvin of France (1509—1564) fanned the flames of reform. At the heart of their convictions was the Latin motto ad fontes, meaning “back to the sources.” The Reformers emphasized the authority of the Bible in all matters of faith and practice.
In response to the Reformation, the Council of Trent (1545—1563) reaffirmed Catholic doctrines like transubstantiation and rejected Protestant doctrines like sola scriptura (“Scripture alone”). While the council addressed corruption among clergy, it also strengthened the office of the pope. In the end, the Reformation marked the second major split in the history of the Church.
Two significant councils in the Contemporary era (eighteenth to twenty-first centuries) are Vatican I (1869—1870) and Vatican II (1962—1965). One outcome of Vatican I was to further strengthen the papacy, as it declared that the pope may speak ex cathedra, i.e., infallibly on matters of faith and morality. A significant outcome of Vatican II was ecumenism, which sought improved relationships with Protestant Christians and other religions. A key figure in the modern era was Pope John Paul II (1920—2005), who was known for his opposition to communism.
In 1992, the Catholic Church reaffirmed its core tenets in The Catechism of the Catholic Church. This reaffirmation demonstrated that, after nearly 2,000 years, the Church would carry its convictions into the twenty-first century, remaining committed to the beliefs and practices that have characterized it for centuries.
