Roman Catholicism did not appear at a single moment in Christian history in the form in which it exists today. Catholics understand their church as standing in continuous succession from the church established by Christ and the apostles, while Eastern Orthodox and Protestant Christians disagree with important Catholic claims about how that continuity should be understood. Historically, however, there was no point in the first few centuries when Christians divided themselves into the familiar modern categories of Catholic, Orthodox, and Protestant.

The history of Roman Catholicism is therefore intertwined with the history of Christianity itself. Its doctrines, institutions, worship, and understanding of church authority developed over many centuries. Some of those developments were widely shared among ancient Christians, while others eventually became points of disagreement that contributed to the divisions of Christianity.

The Early Church

Christianity began in Jerusalem and spread rapidly throughout the Roman Empire. As the apostles died, bishops increasingly occupied important positions of leadership within Christian communities. Among the most influential churches were those associated with major cities such as Rome, Alexandria, Antioch, Jerusalem, and eventually Constantinople.

The church at Rome enjoyed considerable prestige at an early date. Rome was the capital of the empire, and Christian tradition associated the city with the ministries and martyrdoms of both Peter and Paul. Bishops of Rome gradually exercised influence beyond their own local church, although Christians disagree about whether this early prominence represents the beginnings of the later papacy or something considerably more limited.

During these centuries, Christians also worked through major theological controversies concerning the Trinity and the person of Christ. Councils at Nicaea, Constantinople, Ephesus, and Chalcedon produced doctrinal formulations that Roman Catholics continue to affirm along with Eastern Orthodox Christians and most Protestants.

Christianity and the Roman Empire

The situation changed dramatically during the fourth century. After centuries in which Christians had periodically faced persecution, Christianity received legal toleration under Emperor Constantine and eventually became closely associated with the Roman Empire. Bishops now operated in a very different social and political environment.

The collapse of imperial authority in Western Europe further increased the importance of the bishop of Rome. Popes sometimes found themselves performing political and diplomatic functions in addition to their religious responsibilities. Over time, the papacy became one of the most important institutions in Western Europe.

This relationship between church and political power brought opportunities as well as problems. Christianity could build institutions, conduct missions, educate populations, and influence European culture on a scale that had previously been impossible. At the same time, wealth and political authority created opportunities for corruption and conflicts that had very little to do with the Sermon on the Mount.

The Division Between East and West

Christianity in the eastern and western portions of the former Roman world gradually developed in different cultural environments. Western Christianity primarily used Latin, while Eastern Christianity primarily used Greek. Differences also developed concerning theology, worship, church organization, and the authority of the bishop of Rome.

One important dispute concerned the Filioque, a Latin phrase meaning “and the Son,” which Western Christians added to the Nicene Creed’s statement concerning the procession of the Holy Spirit. Eastern Christians objected both to the theology involved and to the alteration of an ecumenical creed without the agreement of an ecumenical council.

Tensions eventually produced what is conventionally called the Great Schism of 1054, although the separation developed over a much longer period. Western Christianity continued under the leadership of Rome, while the Eastern churches developed as what we now call Eastern Orthodoxy. The disastrous sack of Constantinople by Western Crusaders in 1204 made an already damaged relationship considerably worse.

Medieval Catholicism

During the Middle Ages, the Roman Catholic Church became one of the central institutions of Western civilization. Monasteries preserved manuscripts and became centers of education and missionary activity. Universities emerged, and theologians such as Anselm and Thomas Aquinas developed sophisticated systems of Christian theology.

The medieval church also accumulated substantial wealth and political influence. Popes sometimes competed directly with kings and emperors, and controversies developed over who possessed authority to appoint bishops and govern Christian society. The Crusades, the Inquisition, conflicts within the papacy, and abuses among clergy became part of a complicated history containing examples of both remarkable Christian devotion and serious institutional failure.

Calls for reform did not begin with Martin Luther. Christians such as John Wycliffe and Jan Hus criticized aspects of church teaching and authority before the sixteenth century, while reform movements also arose within Catholic religious orders and institutions. By the beginning of the 1500s, dissatisfaction with conditions in the Western church was widespread.

The Protestant Reformation

In 1517, Martin Luther challenged the sale of indulgences in his Ninety-Five Theses. The controversy soon expanded beyond indulgences into fundamental disagreements concerning justification, the authority of Scripture, the sacraments, the priesthood, and the authority of the pope.

Other reform movements appeared under Huldrych Zwingli, John Calvin, the Anabaptists, and English reformers. What began as demands for reform eventually resulted in the permanent fragmentation of Western Christianity. Lutheran, Reformed, Anglican, and other Protestant traditions emerged outside communion with Rome.

The Catholic Church responded through a movement often called the Catholic Reformation or Counter-Reformation. New religious orders appeared, existing institutions were reformed, and Catholic missionaries carried Christianity into new parts of the world. The most important doctrinal response came from the Council of Trent.

The Council of Trent

The Council of Trent, which met in several sessions between 1545 and 1563, became one of the most important councils in Roman Catholic history. It addressed abuses within the church while also defining Catholic teaching in response to Protestant challenges.

Trent clarified Catholic positions concerning Scripture and Tradition, justification, the sacraments, the Mass, and other disputed doctrines. It rejected important Reformation teachings, including Protestant formulations of justification by faith alone and Scripture alone. The council also promoted reforms in the training and discipline of clergy.

Trent helped shape Roman Catholicism for the next several centuries. It did not simply preserve medieval Catholicism unchanged; it contributed to a more clearly defined Catholic identity in a Christian world now permanently divided by the Reformation.

Vatican I

During the nineteenth century, the Catholic Church faced a rapidly changing political and intellectual environment. Nationalism, secular governments, modern philosophy, and the decline of the old European political order all challenged the church’s traditional position.

The First Vatican Council, convened by Pope Pius IX in 1869, addressed questions concerning faith, reason, revelation, and papal authority. Its most famous decision was the formal definition of papal infallibility in 1870 under specific conditions involving definitive teaching on faith or morals.

The council ended prematurely when political events surrounding the unification of Italy interrupted its work. Nevertheless, its definition of papal authority became one of the most distinctive features separating Roman Catholicism from other Christian traditions.

Vatican II

Nearly a century later, Pope John XXIII convened the Second Vatican Council, which met from 1962 to 1965. Vatican II did not abandon traditional Catholic doctrine, but it introduced significant changes in the way the church expressed its faith and related to the modern world.

The council encouraged greater participation by lay Catholics, promoted the use of vernacular languages in worship, emphasized Scripture more strongly in Catholic life, and reshaped Catholic relationships with Protestants, Eastern Orthodox Christians, Jews, and followers of other religions. Its reforms significantly changed the experience of Catholic life and worship in many parts of the world.

Vatican II remains the subject of debate among Catholics themselves. Some believe its reforms were necessary and overdue, while others believe aspects of its implementation weakened important Catholic traditions. More than half a century later, debates about how the council should be interpreted have not entirely disappeared.

Roman Catholicism Today

Today the Catholic Church is a worldwide Christian body consisting of the much larger Latin Church together with a number of Eastern Catholic churches in communion with Rome. Its members worship in virtually every part of the world, and the cultural expression of Catholicism varies enormously from one country to another.

Modern Catholicism therefore carries nearly two thousand years of history with it. The papacy, the Mass, monasteries, medieval theology, Trent, global missions, Vatican I, and Vatican II have all contributed to the church that exists today. Some features Catholics regard as legitimate developments of the apostolic faith are precisely the features other Christians regard as departures from it.

That tension is one of the reasons Catholic history matters. Understanding what Roman Catholicism became requires more than asking what Catholics believe today. It also requires asking how those beliefs and institutions developed, when they developed, and what Christians believed before the disagreements arose. Those are questions we’ll be able to explore much more closely as the Jew & Greek library grows.