Theological terms of the first four centuries

Glossary

The controversies, offices, and watchwords of the early church — thirty terms, each defined from the sources and linked to the figures and texts that carry them.

• Ante-NiceneThe period of church history between the apostolic generation and the Council of Nicaea (AD 325) — the centuries of persecution, the apologists, and…
• ApologistA second-century defender of the faith who addressed reasoned pleas (apologiai) to emperors and philosophers, arguing that Christians were neither…
• Apostolic FathersThe earliest Christian writers outside the New Testament — the generation taught by the apostles themselves, whose letters and manuals (Clement…
• Apostolic SuccessionThe unbroken chain of bishops teaching in each church from the apostles onward — the second century’s public test of authentic doctrine against…
• AnathemaA formal conciliar condemnation cutting a teaching or teacher off from communion. The Council of Nicaea closed its creed with anathemas against the…
• ArianismThe teaching of Arius of Alexandria that the Son of God is the first and highest creature — “there was when he was not” — rather than eternally God.…
• Bishop (Episkopos)The “overseer” of a local church, guardian of its teaching and eucharist. By Ignatius of Antioch (c. 110) the single bishop with his presbyters and…
• Canon of ScriptureThe recognized list of books read as Scripture in the churches. The Muratorian Fragment (c. 170–200) preserves the earliest surviving canon list…
• CatechumenA convert under instruction, admitted to the church’s teaching but not yet to baptism or the eucharist. The catechumenate could last years…
• ConfessorOne who confessed the faith under interrogation or torture and survived — honored beside the martyrs, and influential enough that lapsed Christians…
• The Didache“The Teaching of the Twelve Apostles” — the earliest surviving church manual (c. AD 50–70), covering the Two Ways, baptism, fasting, the eucharistic…
• DocetismThe claim that Christ only seemed (dokein) to have flesh and to suffer. Ignatius of Antioch attacked it as the undoing of the gospel: a phantom…
• DonatismThe North African schism after the Great Persecution: rejecting clergy ordained by alleged traditores, the party of Majorinus and Donatus set up a…
• Ecumenical CouncilA synod of bishops from the whole inhabited world (oikoumene), convened to settle doctrine for every church. Nicaea (325), summoned by Constantine…
• GnosticismA family of second-century movements offering salvation through secret knowledge (gnosis): a lesser demiurge made the material world, and the elect…
• HeresiarchThe founder or arch-teacher of a heresy. This archive catalogues them from the primary sources — often preserved only in the books written to refute…
• Homoousion“Of the same substance” — the Nicene Creed’s decisive word: the Son is of the very being of the Father, not a creature. The rival homoiousion (“of…
• Hypostatic UnionThe doctrine that in the one person (hypostasis) of Christ the divine and human natures are united without confusion. Formalized at Chalcedon (451)…
• The Lapsed (Lapsi)Christians who sacrificed, obtained false certificates, or surrendered Scriptures under persecution. Whether and how they could be restored split the…
• LibellusA certificate that the bearer had sacrificed to the gods, issued by imperial commissions under Decius (250). Several originals survive on papyrus…
• MarcionismMarcion of Sinope’s doctrine that the just Creator God of the Old Testament is not the good Father of Jesus Christ, with a canon cut down to an…
• MartyrA “witness” who sealed the confession of Christ with death. The court records (acta) and passiones of the martyrs are among the most reliable…
• Melitian SchismThe Egyptian schism of Melitius of Lycopolis, who ordained clergy across other bishops’ sees during the Great Persecution and opposed the gentler…
• Modalism (Sabellianism)The teaching that Father, Son, and Spirit are three modes of one divine person — so that, pressed to its end, the Father suffered on the cross.…
• Montanism (the New Prophecy)The Phrygian prophetic movement of Montanus, Prisca, and Maximilla, claiming fresh revelation of the Paraclete with severe fasting and discipline. It…
• NovatianismThe rigorist schism of Novatian, rival bishop of Rome to Cornelius (251), refusing restoration to any who lapsed in the Decian persecution. His…
• Pneumatomachians“Spirit-fighters” — those who accepted the Son’s deity but denied that of the Holy Spirit, associated with Eustathius of Sebaste. Answered by…
• QuartodecimanismThe Asian practice of keeping Pascha on Nisan 14, the day of the Jewish Passover, whatever the weekday — defended by Polycrates of Ephesus from…
• SeptuagintThe Greek Old Testament, the Bible of the early church. Origen’s Hexapla set it beside the later Jewish versions of Aquila and Symmachus in parallel…
• TraditorOne who “handed over” the Scriptures or church property to the authorities during the Great Persecution. The charge — true or alleged — against…