Skip to main content
Orthodox Knowledge

Orthodox Christianity Knowledge Repository

A searchable corpus of Orthodox Christian sources, scripture, ecumenical councils, the church fathers, and the saints, with three ways in: keyword search, AI-powered Q&A, and hand-curated topical collections.

Today on the Orthodox calendar

Martyr Aquilina of Byblos

Saturday, June 13, 2026

Fish allowed· Fish, Wine and Oil are Allowed· Eighth Tone
  • Saint Triphyllius, bishop of Leucosia (Nicosia) in Cyprus (370)
  • St Anna and her son John (5h c.)
Epistle
Romans 3.19-26
Gospel
Matthew 7.1-8
Full day →Pascha: Apr 12, 2026
Free · no account

Search the corpus

Keyword search across 102,906 paragraph-level passages from 268 works by 76 authors, scripture (OT/NT), the seven ecumenical councils, the apostolic and ante-Nicene fathers, the post-Nicene Greek and Latin fathers, the Syriac tradition, and more. Filter by work, jump straight to the passage in context.

AI · bring-your-own-key or membership

Ask the Fathers

Ask a theological question in plain English. The assistant uses semantic search to retrieve the most relevant passages from the corpus, then answers grounded in them with inline citations, no hallucinated quotes, no flattened disagreements. Powered by Claude Sonnet 4.6. Free with your own Anthropic API key, or use the project's key as a Supporter ($5/mo).

Free · no account

Browse topics

Hand-curated topical collections, eucharistic theology, theosis, apostolic succession, Marian doctrine, iconography, and more, grouping verses, council definitions, and patristic positions under each theme. The fastest way in if you'd rather start with a question than a keyword.

Current corpus

  • Old Testament: 52 books (Septuagint, Updated Brenton English)
  • New Testament: 27 books (World English Bible, Greek Majority Text)
  • Apostolic Fathers: 15 works (Lightfoot, c. 95–175 AD)
  • Early Apologists: Justin Martyr, Tatian, Athenagoras, Theophilus (ANF, c. 155–180 AD)
  • Ante-Nicene Theologians: St Irenaeus of Lyons; Clement of Alexandria; Tertullian of Carthage (32 works); St Hippolytus of Rome; Origen of Alexandria (received critically per the 553 anathemas); St Cyprian of Carthage (83 epistles + treatises)
  • Ecumenical Councils: All seven (Nicaea I, Constantinople I, Ephesus, Chalcedon, Constantinople II & III, Nicaea II) + the Quinisext (Trullo) Council + the locally accepted canons of Ancyra, Gangra, Sardica, Carthage et al. (NPNF II.14)
  • Post-Nicene Greek Fathers: St Athanasius the Great (18 works); St Basil the Great (On the Holy Spirit, Hexaemeron, 356 Letters); St Gregory the Theologian (24 Orations, Letters); St Gregory of Nyssa (Dogmatic, Ascetic, Philosophical, the Great Catechism, …); St Cyril of Jerusalem (24 Catechetical Lectures); St John Chrysostom (22 works, On the Priesthood, the Statues, complete Homilies on Matthew, John, Acts, the Pauline epistles, Hebrews) (NPNF I.9–14); St Cyril of Alexandria: architect of Orthodox Christology, who led the Council of Ephesus (Commentary on John in 12 books, Five Tomes Against Nestorius, That Christ is One, Scholia on the Incarnation, Pusey LFC 1874–1885); St John of Damascus (Exposition of the Orthodox Faith, NPNF II.9; Three Treatises on the Divine Images; Three Homilies on the Dormition, Allies 1898)
  • Corpus Areopagiticum: Pseudo-Dionysius the Areopagite (c. 500 AD) (received critically, pseudonymous, cited extensively by St Maximus, St John of Damascus, and the hesychast tradition): Divine Names, Mystical Theology, Celestial Hierarchy, Ecclesiastical Hierarchy, Letters (Parker 1897–1899)
  • Early Church Historians & Latin Fathers (4th–5th c.): Eusebius of Caesarea (Church History, Life of Constantine), Socrates Scholasticus, Sozomen, Blessed Theodoret of Cyrus, St Hilary of Poitiers (De Trinitate, De Synodis, Psalm Homilies), St Jerome (Letters, Treatises, Lives of Illustrious Men), Rufinus of Aquileia (NPNF II.1–3, II.9)
  • St Augustine of Hippo: Confessions, City of God, Tractates on John, Enarrationes on the Psalms, Sermon on the Mount, Harmony of the Gospels, Sermons on the NT, Letters, Doctrinal/Moral Treatises (including De Trinitate, Enchiridion, On Catechizing the Uninstructed), Anti-Manichaean, Anti-Donatist, Anti-Pelagian (NPNF I.1–8)
  • Other Latin Fathers & Bridges: St Ambrose of Milan (Dogmatic Treatises & Letters); St John Cassian (Institutes, Conferences, On the Incarnation); St Vincent of Lérins (the Commonitorium); Sulpitius Severus (Life of St Martin); St Leo the Great (Tome, Letters & Sermons); St Gregory the Great the Dialogist (Pastoral Rule, Letters) (NPNF II.10–13)
  • Syriac Fathers: St Ephraim the Syrian (Nisibene Hymns, Nativity and Epiphany Hymns, The Pearl, Homilies); Aphrahat the Persian Sage (Select Demonstrations) (NPNF II.13)
  • Late ante-Nicene + early liturgical sources: St Methodius of Olympus (Symposium, On the Resurrection); St Dionysius the Great of Alexandria; St Peter of Alexandria; St Alexander of Alexandria (anti-Arian letters); Lactantius (Divine Institutes, On the Death of the Persecutors); the Apostolic Constitutions; the early Divine Liturgies of St James, St Mark, and the Clementine (ANF Vols 6–7)
  • 2nd-c. Fragments: Papias of Hierapolis, Quadratus, Melito of Sardis, Hegesippus, Polycrates, Pantaenus (ANF Vols 1 & 8)

Total: over 110,000 paragraph-level passages across 280+ works by 78 authors, the patristic corpus through the 8th century in a single searchable, semantically embedded, work-filterable knowledge base. For the exact current counts and the full work index, browse the library.

Browse the full library →

Not yet in the corpus

Most of the gaps below are out of public-domain English. The cost estimates are what it would take to translate the Greek public-domain source via Claude Opus and ingest the result, padded ~40% to cover re-runs, quality passes, and API price changes. Surplus on any item rolls forward to the next. Donations toward any item move it from this list into the corpus above.

  • St Maximus the Confessor
    Ambigua, Mystagogy, Centuries on Charity, Questions to Thalassius, the architecture of theosis and the cosmic Christ.
    $350
  • St John Climacus
    The Ladder of Divine Ascent, the foundational Orthodox ascetic text.
    $75
  • St Symeon the New Theologian
    Hymns of Divine Love, Discourses, Theological & Ethical Treatises.
    $300
  • St Gregory Palamas
    Triads in Defense of the Holy Hesychasts, 150 Chapters, Homilies, the essence/energies distinction.
    $350
  • Desert tradition
    Apophthegmata Patrum (Sayings), Macarius, Anthony, Poemen, Sisoes et al., plus the Macarian Homilies (foundational for hesychast theology) and Palladius's Lausiac History (early monastic biographies).
    $225
  • Philokalia
    The 5-volume Greek anthology compiled by Sts Nikodimos & Makarios, most of the hesychast tradition in one collection.
    $500
  • Select feast hymnography
    Hymns for the twelve great feasts (Nativity of the Theotokos, Exaltation of the Cross, Theophany, Annunciation, Pascha, et al.), apolytikia, kontakia, and select stichera from the Festal Menaion tradition. Narrowed from the full liturgical corpus since poetic Byzantine Greek doesn't translate well by AI alone.
    $200
  • Brief synaxaria readings
    The short daily commemorations that introduce each saint's feast day across the Orthodox liturgical year, translated from the public-domain Greek Synaxaria of Constantinople. Concise paragraph-length entries, not full hagiographies.
    $150
  • Influential pseudepigrapha (received critically)
    Protoevangelium of James (source of Orthodox Marian tradition, Joachim and Anna, the Entrance into the Temple, perpetual virginity) plus select narrative apocrypha (Acts of John, Andrew, Thomas) that shaped Orthodox hagiography. Excludes the Gnostic gospels.
    $75

Total to finish through the 14th c.: ~$2,225

Contribute →