History

The Christian Church begins with the resurrection of Jesus Christ and the descent of the Holy Spirit at Pentecost (Acts 2), when the apostles first proclaimed the Gospel publicly in Jerusalem. Leadership rested with the Twelve whom Christ himself had chosen and commissioned, and the earliest community devoted itself, in Luke's words, to "the apostles' teaching and fellowship, to the breaking of bread and the prayers" (Acts 2:42). No New Testament writings yet existed; the apostolic preaching was carried by the spoken word and the authority of those who had witnessed the risen Christ.

Beginning around AD 50, Paul of Tarsus, converted a few years after the crucifixion, began writing letters to the churches he founded across Asia Minor, Greece, and beyond. His epistles are the earliest surviving Christian documents of any kind, predating the Gospels, and give the first written witness to how the apostolic generation understood the Gospel, the sacraments, and the shape of Christian community life.

In AD 70, Roman forces under Titus destroyed Jerusalem and the Second Temple, ending Temple sacrifice permanently and scattering the Jewish Christian community that had been centered there. The event marks a decisive turning point after which the Church's center of gravity shifted increasingly toward the Gentile world, and it forms the backdrop against which the Gospels reached their final written form.

Around AD 95, Clement of Rome wrote to the church at Corinth to address a dispute in which younger members had removed legitimately appointed presbyters from office. His letter is the earliest surviving Christian document outside the New Testament, and its argument -- that the apostles appointed leaders and made provision for their successors -- is the earliest extant witness to what would later be articulated as apostolic succession.

Around AD 107, Ignatius, bishop of Antioch, was taken to Rome for execution. Along the way he wrote seven letters to churches he passed, urging unity around each local bishop and giving the earliest clear witness to a single bishop presiding over each Christian community, as well as early testimony to belief in the Eucharist as the flesh of Christ.

Justin Martyr, a former philosopher converted to Christianity, wrote his First Apology around AD 155 to defend Christian belief and practice to the Roman emperor. It contains the earliest surviving detailed outside description of a Christian Sunday liturgy, including the reading of Scripture, communal prayer, and the Eucharist.

Writing around AD 180, Irenaeus, bishop of Lyons, composed Against Heresies to refute Gnostic teachers who claimed access to secret apostolic traditions. His central argument -- that the true apostolic teaching is the one publicly handed down through the known, traceable succession of bishops in every church -- makes him the clearest early witness to both apostolic succession and the rule of faith as public and verifiable rather than secret.

The First Council of Nicaea, convened in AD 325, was the Church's first ecumenical council. Called to address the teaching of Arius, who denied that the Son was fully divine, the council produced the first form of what became the Nicene Creed and declared the Son to be "of one substance" (homoousios) with the Father.

The First Council of Constantinople, in AD 381, reaffirmed and expanded Nicaea's teaching, completing the Creed still recited at Mass today and formally addressing the divinity of the Holy Spirit against those who denied it.

The Council of Ephesus, in AD 431, condemned the teaching of Nestorius, who separated Christ's divine and human natures so sharply that he objected to calling Mary "Mother of God" (Theotokos). The council affirmed that title, teaching that the one person of Christ is truly divine, so that Mary who bore him may rightly be called God's Mother.

The Council of Chalcedon, in AD 451, defined that Christ is one person in two natures, divine and human, "without confusion, without change, without division, without separation." The Chalcedonian Definition remains the classical Christological formula for the vast majority of Christian churches, East and West.

The Council of Trent met across several sessions between 1545 and 1563, in response to the Protestant Reformation. It defined Catholic teaching on Scripture and Tradition, justification, and the sacraments -- including, in its thirteenth session (1551), the Real Presence of Christ in the Eucharist -- and initiated wide-ranging reforms of clergy formation, discipline, and liturgy.

The First Vatican Council, convened from 1869 to 1870, defined the doctrine of papal infallibility -- that the pope, under carefully specified conditions, teaches without error when he solemnly defines a doctrine of faith or morals for the whole Church. The council was cut short by the outbreak of the Franco-Prussian War and the occupation of Rome, and was never formally closed.

The Second Vatican Council, held from 1962 to 1965, was called to address the Church's relationship to the modern world. Its documents reformed the liturgy, articulated a renewed theology of the Church and the laity, and addressed relations with other Christians, other religions, and the modern world, reshaping Catholic life and practice into the twenty-first century.

Promulgated in 1992, the Catechism of the Catholic Church gathered the Church's teaching on faith and morals into a single authoritative reference, drawing on Scripture, the Fathers, the councils, and the Magisterium. It remains the standard modern point of reference for what the Catholic Church teaches and why.