Early Church & Councils

And they devoted themselves to the apostles’ teaching and the fellowship, to the breaking of bread and the prayers. And awe came upon every soul, and many wonders and signs were being done through the apostles. — Acts 2:42–43

The first millennium of Christianity saw the church grow from a persecuted Jewish sect into the dominant faith of the Roman world. Through martyrdom, theological controversy, and ecumenical councils, the church articulated the core doctrines that Christians of all traditions continue to confess.

The New Testament word for “church” is ekklēsia (ἐκκλησία), meaning “assembly” or “those called out.” In secular Greek it referred to a civic assembly of citizens summoned for public deliberation. The early Christians adopted this word to describe the people of God gathered by His call — not a building or an institution, but a living community united in Christ.

The Apostolic Age (30–100 AD)

The church was born at Pentecost, when the Holy Spirit descended upon the disciples in Jerusalem (Acts 2). From this foundation:

• The apostles preached the gospel first to Jews and then to Gentiles, establishing churches throughout the Roman Empire
• Paul’s missionary journeys planted congregations across Asia Minor, Greece, and eventually Rome
• The New Testament documents — Gospels, epistles, and Revelation — were written during this period
• The destruction of the Jerusalem temple in 70 AD marked a decisive break between the church and Judaism
• By the end of the first century, Christian communities existed from Rome to Mesopotamia

The Apostolic Fathers and Apologists (100–300 AD)

After the apostles died, the next generations of leaders preserved and defended the faith:

• Clement of Rome (c. 96 AD) — wrote to the Corinthian church, emphasizing order and apostolic succession
• Ignatius of Antioch (c. 35–108 AD) — wrote seven letters on his way to martyrdom, stressing the authority of bishops and the real presence of Christ in the Eucharist
• Polycarp of Smyrna (c. 69–155 AD) — a disciple of the apostle John, martyred at age 86, whose faithfulness inspired generations
• Justin Martyr (c. 100–165 AD) — a philosopher-convert who wrote the earliest detailed descriptions of Christian worship and defended the faith before Roman authorities
• Irenaeus of Lyon (c. 130–202 AD) — combated Gnosticism in his work Against Heresies, articulating the rule of faith and the authority of apostolic tradition
• Tertullian (c. 155–220 AD) — a Latin theologian who coined the term trinitas (Trinity) and shaped Western theological vocabulary. Earlier, Theophilus of Antioch (c. 180 AD) had used the Greek equivalent trias (τριάς).
• Origen of Alexandria (c. 185–253 AD) — a prolific scholar who advanced biblical interpretation and systematic theology, though some of his speculative views were later condemned

Persecution and Martyrdom

For nearly three centuries, Christians faced intermittent persecution from the Roman state:

• Nero (64 AD) — blamed Christians for the Great Fire of Rome; Peter and Paul were likely martyred during this period
• Domitian (81–96 AD) — demanded emperor worship, leading to the exile of the apostle John to Patmos
• Trajan to Marcus Aurelius (98–180 AD) — Christians were not actively sought out but were punished if accused and if they refused to sacrifice to Roman gods
• Decius and Valerian (250–260 AD) — empire-wide persecution requiring all citizens to sacrifice to the gods
• The Great Persecution under Diocletian (303–311 AD) — the most severe and systematic persecution, destroying churches and Scriptures and imprisoning clergy

The blood of the martyrs became the seed of the church. The Greek word martys (μάρτυς) originally meant simply “witness” — one who testifies to what they have seen and known. Because so many early witnesses sealed their testimony with their lives, the word came to mean one who dies for the faith. Their courage demonstrated that the Christian faith was worth dying for and drew many to belief.

The Turning Point: Constantine and the Edict of Milan (313 AD)

Emperor Constantine’s conversion transformed the church’s relationship to political power:

• The Edict of Milan (313 AD) granted religious toleration throughout the empire
• Constantine convened the Council of Nicaea (325 AD) to address the Arian controversy
• Christianity became the official religion of the Roman Empire under Theodosius I (380 AD)
• This new status brought both benefits and temptations — the church gained resources and influence but also faced the danger of worldly compromise

The Seven Ecumenical Councils

The ecumenical councils defined orthodox Christian doctrine, and their decisions are accepted by Eastern Orthodox, Roman Catholic, and most Protestant traditions:

First Council of Nicaea (325 AD)

• Condemned Arianism — the teaching that the Son was a created being
• Affirmed that the Son is homoousios (ὁμοούσιος) — “of the same substance” or “of one being” — with the Father. This term was chosen against the Arian position that the Son was heteroousios (ἑτεροούσιος, “of different substance”). A mediating party proposed homoiousios (ὁμοιούσιος) — “of similar substance” — but Nicaea insisted on the stronger homoousios: a single iota (ι) marking the difference between full equality with the Father and mere resemblance.
• Produced the original Nicene Creed

First Council of Constantinople (381 AD)

• Expanded the Nicene Creed into its present form (the Niceno-Constantinopolitan Creed)
• Affirmed the full divinity of the Holy Spirit against the Pneumatomachians (πνευματομάχοι, “Spirit-fighters,” also called Macedonians)
• Declared Constantinople second in honor after Rome

Council of Ephesus (431 AD)

• Condemned Nestorianism — the teaching that Christ was two separate persons
• Affirmed Mary as Theotokos (Θεοτόκος) — “God-bearer” or “Mother of God” — a title affirming the unity of Christ’s person, not Marian worship

Council of Chalcedon (451 AD)

• Condemned Eutychianism — the teaching that Christ’s human nature was absorbed into His divine nature, leaving only one nature. (Note: the Oriental Orthodox churches, which rejected Chalcedon, prefer the term miaphysite — confessing “one united nature” — and reject the label monophysite, which they regard as Eutychian. Modern dialogue has shown that the disagreement may be more terminological than substantive.)
• Produced the Chalcedonian Definition: Christ is one person in two natures — fully divine and fully human in the incarnation — “without confusion, without change, without division, without separation”
• This definition remains the standard Christological formulation for most of Christianity

Second Council of Constantinople (553 AD)

• Condemned the “Three Chapters” — writings sympathetic to Nestorianism
• Reaffirmed the decisions of Chalcedon

Third Council of Constantinople (680–681 AD)

• Condemned Monothelitism — the teaching that Christ had only one will
• Affirmed that Christ has two wills, divine and human, in harmony

Second Council of Nicaea (787 AD)

• Addressed the Iconoclasm controversy
• Distinguished between latreia (λατρεία) — worship due to God alone — and proskynesis (προσκύνησις) — veneration or honor given to icons
• Affirmed the veneration of icons as permissible (though Protestants generally disagree on this point)

Key Theological Giants

• Athanasius of Alexandria (c. 296–373 AD) — the champion of Nicene orthodoxy who was exiled five times for defending the full divinity of Christ: “Athanasius contra mundum” — Athanasius against the world
• The Cappadocian Fathers — Basil of Caesarea (c. 330–379), Gregory of Nazianzus (c. 329–390), and Gregory of Nyssa (c. 335–395) — clarified Trinitarian theology by distinguishing between ousia (οὐσία) — essence — and hypostasis (ὑπόστασις) — person
• Augustine of Hippo (354–430 AD) — perhaps the most influential Western theologian, whose works on grace, the Trinity, the City of God, and original sin shaped both Catholic and Protestant thought
• John Chrysostom (c. 347–407 AD) — “Golden Mouth,” the greatest preacher of the early church, known for his expository sermons and his courage in rebuking imperial sin

The East-West Schism (1054 AD)

The formal split between Eastern Orthodoxy and Roman Catholicism resulted from centuries of growing tensions:

• Theological disputes — the filioque (Latin: “and from the Son”) controversy: the Western church added this clause to the Nicene Creed’s statement that the Holy Spirit “proceeds from the Father,” so that it read “proceeds from the Father and the Son.” The East regarded this as both an unauthorized alteration of conciliar doctrine and a theological error. The original Greek creed used ekporeuomenon (ἐκπορευόμενον) — “proceeding” — with the Father alone as the sole source (monarchia) of the Spirit’s procession. The West argued that the filioque safeguarded the Son’s full divinity, while the East maintained that it confused the distinct personal properties of the Father and compromised His unique role as sole origin of the Trinity
• Ecclesiological disputes — the growing claims of papal supremacy by Rome versus the conciliar model of authority in the East
• Cultural and political factors — the fall of the Western Roman Empire, linguistic division between Latin West and Greek East, and competing political interests
• The mutual excommunications of 1054 — Cardinal Humbert and Patriarch Michael Cerularius excommunicated each other, formalizing a division that had been developing for centuries

The schism remains unhealed to this day, though modern ecumenical dialogue has brought significant progress. In 1965, Pope Paul VI and Patriarch Athenagoras mutually lifted the excommunications of 1054.

But God, being rich in mercy, because of the great love with which he loved us, even when we were dead in our trespasses, made us alive together with Christ — by grace you have been saved. — Ephesians 2:4–5