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The biblical canon: the agreed list of books
Athanasius's 27-book list AD 367; councils 393, 397· Council, creed or writing· Books & writings
Historical recordConfirmed by archaeology, outside sources or contemporary records.
The gradual process by which churches agreed which books belong in the Bible, settled for the New Testament by about 400.
See it on the Bible & Christianity map →What it is
'Canon' is Greek for 'measuring rod'. No single vote chose the books. By about 200 the four Gospels and Paul's letters were widely accepted; Hebrews, James, 2 Peter, 2–3 John, Jude and Revelation were disputed longer. The tests were apostolic origin, wide use in worship, and agreement with the faith. Athanasius listed the 27 New Testament books in 367; councils at Hippo (393) and Carthage (397) confirmed them.
Why it matters
It made the Bible one book. All major churches share the 27 New Testament books but differ on the Old Testament: Protestants 39 books, Catholics 46, Orthodox a few more.
Think of it like
Like a chain of title: no single deed created it, but over generations a recognized record settled what belongs.
Sources and history
Ancient lists survive: the Muratorian Fragment, Eusebius's Church History (c. 325), Athanasius's 39th Festal Letter and the council records, plus early complete Bibles like Codex Sinaiticus (c. 350).
Questions and debates
Whether the church 'created' the canon or 'recognized' it divides Catholic and Protestant framing. The Muratorian Fragment's date (c. 180 or 4th century) is debated.
Inside this (2)
Connections (6)
▸The Hebrew Bible (Old Testament) became the Old Testament in The biblical canon: the agreed list of booksHistorical record
The connection
Christians kept the Jewish scriptures as their 'Old Testament'. Most early churches read them in the Greek Septuagint, which included extra books such as Tobit, Judith, Wisdom and Maccabees. Marcion's call to drop them was rejected. Jerome preferred the shorter Hebrew list; Augustine and the African councils kept the longer one. That difference still separates Protestant and Catholic Bibles.
When and where
Melito of Sardis listed the 'books of the Old Covenant' around 170; councils at Hippo (393) and Carthage (397); Luther set the extra books apart in 1534; Trent confirmed them in 1546.
Historical evidence
Melito's list is preserved by Eusebius; early Christian Bibles such as Codex Sinaiticus and Vaticanus contain the extra books alongside the Hebrew ones.
Questions and debates
Whether a wider 'Alexandrian' Jewish canon lay behind the Septuagint, as scholars once thought, is now doubted; Christian lists of the extra books varied for centuries.
▸The New Testament was fixed at 27 books by The biblical canon: the agreed list of booksHistorical record
The connection
The 27 books were written separately (about AD 50–120) and circulated on their own. Churches gradually agreed on the core, then argued over the edges: Hebrews, James, 2 Peter, 2–3 John, Jude and Revelation. Athanasius's list (367) and the African councils (393, 397) settled on the 27 that Catholic, Orthodox and Protestant Bibles all share.
When and where
Across the Mediterranean, 2nd–4th centuries; key moments at Alexandria (367), Hippo (393) and Carthage (397).
Historical evidence
Surviving lists show the process: the Muratorian Fragment, Origen's views reported by Eusebius, Eusebius's own sorting (c. 325), Athanasius's Festal Letter and the council canons.
Questions and debates
Syriac churches long used a 22-book New Testament without 2 Peter, 2–3 John, Jude or Revelation; why some books like the Shepherd of Hermas dropped out is debated.
▸The biblical canon: the agreed list of books was rendered into Latin in Jerome's Latin VulgateHistorical record
The connection
Jerome turned the agreed books into Latin, revising the Gospels in Rome (382–384), then translating the Old Testament from Hebrew in Bethlehem (about 390–405). He judged the extra Septuagint books as useful but not scripture; the church kept them in the Vulgate anyway. The Vulgate's contents became the Western Bible, and Trent later used them to define the Catholic canon.
When and where
Rome and Bethlehem, 382–405, commissioned by Pope Damasus I.
Historical evidence
Jerome's prefaces, such as his 'Helmeted Preface' to Samuel and Kings (c. 391), set out his view of the canon; early manuscripts show the contents.
Questions and debates
Jerome's doubts about the extra books later supported the Protestant choice to set them aside, while Catholics followed the church's long use; both cite him.
▸Gnostics and Marcion spurred the church to define The biblical canon: the agreed list of booksMostly agreed by scholars
The connection
Marcion's list of around 140, an edited Luke plus ten letters of Paul and no Old Testament, is the first known Christian canon. Gnostic groups circulated secret gospels. In response, leaders like Irenaeus insisted on four Gospels, on books with apostolic links read widely in churches, and on keeping the Old Testament.
When and where
Rome, around 140–144, where Marcion was expelled; Lyon, Gaul, around 180, where Irenaeus wrote Against Heresies.
How do we know?
Irenaeus and Tertullian's Against Marcion (c. 207) describe Marcion's canon in detail; the historian Adolf von Harnack (1921) argued Marcion forced the church's hand.
Questions and debates
Did Marcion trigger the canon or merely speed up a process already under way? Some scholars even argue his 'Luke' was an earlier version, not an edit.
▸The biblical canon: the agreed list of books was formally fixed for Catholics at Council of Trent and the Catholic ReformationHistorical record
The connection
Protestants had moved seven Old Testament books, such as Tobit and 1–2 Maccabees, out of their Bibles' main text as 'Apocrypha'. Trent answered on April 8, 1546, listing all 73 books as fully Scripture and condemning anyone who rejected them. Earlier councils (Hippo 393, Carthage 397, Florence 1442) had listed the same books, but Trent made the list binding dogma.
When and where
Trent, northern Italy, at the council's fourth session, April 8, 1546, in the decree 'On the Canonical Scriptures'.
Historical evidence
The decree's text survives and names each book; Luther's 1534 Bible, which grouped the same books as 'Apocrypha', shows what it was answering.
Questions and debates
Orthodox churches accept a few more books (such as 3 Maccabees); Protestants follow the shorter Hebrew canon. Which canon the earliest church used is still debated.
▸Athanasius of Alexandria first listed the 27 New Testament books of The biblical canon: the agreed list of booksHistorical record
The connection
In his 39th Festal Letter, sent for Easter 367, Athanasius listed the books to be read as scripture, the first known list matching exactly today's 27 New Testament books: 'Let no one add to these or take away.' He named other books, like the Shepherd of Hermas, as useful for new believers but not scripture.
When and where
Alexandria, Egypt, Easter 367, sent to churches and monasteries across Egypt.
Historical evidence
The letter survives in Greek fragments and fuller Coptic copies; later collections of church law include its list.
Questions and debates
Whether he recorded a consensus or imposed one is debated; some suggest the Nag Hammadi books were hidden soon after his letter, but that is unproven.