- 1st Century :
Jesus is born (4-7 BC). Preaching, selection of the Apostles, and first followers (30 AD). In Jerusalem: Eucharist, Passion, Resurrection, and Ascension. Pentecost: the "public presentation" of the Church, first among Jews, and then among Gentiles. First persecutions (martyrdom of St. Stephen, James the Lesser) and first expansion of Christianity beyond Judea and Galilee. New Testament writings: gospels and letters. First Christian communities (Jerusalem, Antioch, Ephesus, Rome…). Gradual separation from Judaism.
- 2nd Century :
Expansion and diversification: Christianity spreads to regions beyond the Roman Empire. Periods of intense persecution (under Trajan and Marcus Aurelius). Early Christian writers defend the faith (the apologists: Justin Martyr, Tertullian, and others). Formation of the Biblical Canon. Development of liturgy. First heresies: a) "Judaizers" (believed the Law of Moses was necessary for salvation); b) "Gnostics" (dualism: there is a "good God" and an "evil god"; they were rigorists); c) "Millenarianism" (expected the second coming of Jesus Christ to establish a new kingdom lasting a thousand years).
- 3rd Century :
Expansion. Conversions across all social classes. Christianity’s growing influence. Severe persecutions (under Emperors Decius and Diocletian). The Church's ecclesiastical structure consolidates. Greater formalization of liturgical and sacramental practices. The rise of asceticism and monastic practices (Saint Anthony the Great). Christianity’s influence grows within the Empire. Heresies: a) "Schismatics" (due to penitential rigorism); b) "Monarchianism" (Christ is only a man).
- 4th Century :
Edict of Milan (313): legalizes Christianity. Under Emperor Theodosius, Christianity becomes the official religion of the Roman Empire (380). Doctrinal controversies: a) “Arianism” (the Son is not consubstantial with the Father); b) “Macedonianism” (denies the divinity of the Son and the Holy Spirit). First ecumenical councils: Nicaea (325) and Constantinople (381). The Creed is formulated. Primacy of the sees of Rome, Constantinople, Alexandria, Antioch, and Jerusalem. Construction of great basilicas. Rise of monasticism. Codification of the Biblical Canon. Christianity influences culture, laws, and institutions. Division of the Empire.
- 5th Century :
The Western Roman Empire falls (476 A.D.) under the pressure of barbarian tribes. The Church assumes a central role in culture and social order. The authority and prestige of the pope, bishop of Rome, increase (notably Leo the Great). More ecumenical councils are held: Ephesus (431) and Chalcedon (451). Theological disputes arise between the Western and Eastern Churches. Heresies emerge: a) Pelagianism (denial of original sin); b) Nestorianism (Jesus and the Son of God are seen as two distinct persons; the Virgin is not acknowledged as “Mother of God”); c) Monophysitism (belief in a single nature in Christ: the divine). Christianity expands and encounters other cultures (Europe, North Africa). Saints play a key role, and the veneration of relics spreads. Monasteries are founded as centers of cultural dissemination. Biblical and theological texts are translated and transmitted.
- 6th Century :
Christianity becomes consolidated in Europe. Barbarian peoples convert. Monasticism develops significantly. In the West, the authority and influence of the Roman Pontiff grow, especially amid the weakening of political power. Ecumenical councils continue, addressing Christological and Trinitarian theological disputes. The Christianization of, and encounters with, non-Christian cultures (Northern Europe, other parts of Africa and Asia) proceed. Liturgical development takes shape. In the East, the Byzantine Empire remains strong and closely tied to the Eastern Church. Monasteries and ecclesiastical schools play a key cultural role.
- 7th Century :
Expansion of Islam; loss of Christian territories and resulting tensions. Flourishing of monasticism in Eastern Christianity (also in areas under Muslim influence, helping to preserve ancient texts). Fragmentation of the former Western Empire. Support of the Frankish kings for the papacy. Missionary drive: Christianization of the Germanic peoples. Heresies: Monothelitism (only one will in Christ — the divine).
- 8th Century :
Consolidation of the relationship (tending toward unification) between Church and State, especially with the Frankish dynasty: Charlemagne crowned Emperor by the Pope (A.D. 800); the papacy strengthens its position in the West. Eastern Empire (Byzantium): iconoclastic controversy (against the veneration of images). Continued expansion of Islam. Ongoing Christianization of Central and Northern Europe (mission of St. Boniface). Church reforms (clergy discipline, liturgy). Development of religious architecture.