The Making of Scripture
How We Got the Bible
The Bible did not fall from the sky as a single bound book. It came together over more than a thousand years, and the Church herself played the decisive role in recognizing which books belonged.
Before there was a "canon"
"Canon" comes from a Greek word for a measuring rod — a standard. Long before Christians spoke of a biblical canon, the Church already existed, worshipped, and handed on the apostolic faith orally and through her bishops, exactly as St. Paul instructed: "hold to the traditions which you were taught, either by word of mouth or by letter" (2 Thessalonians 2:15). The New Testament books themselves were written by members of this already-existing, already-teaching Church.
The Old Testament canon
By the time of Christ, Greek-speaking Jews used a Greek translation of the Hebrew Scriptures called the Septuagint, which included several additional books and passages — Tobit, Judith, Wisdom, Sirach, Baruch, 1–2 Maccabees, and additions to Esther and Daniel — often called the deuterocanonical ("second canon") books. This was the version of the Old Testament most quoted by the New Testament authors and used throughout the early Church. Centuries later, a council of rabbis at Jamnia (c. 90 AD), reacting partly against a Christian movement that had embraced the Septuagint, favored a narrower Hebrew list; the Protestant Reformers, in the sixteenth century, followed that narrower Jewish canon instead of the Church's long-standing practice.
The New Testament canon
Recognizing the 27 books of the New Testament took longer than many assume. Early Christians widely agreed on the four Gospels, Acts, and Paul's major letters fairly quickly, but debated the status of books like Hebrews, James, 2 Peter, 2–3 John, Jude, and Revelation well into the fourth century — while firmly rejecting later Gnostic forgeries like the "Gospel of Thomas." The criteria used were apostolic origin (written by an apostle or a close associate), consistency with the faith already handed down, and consistent liturgical use across the churches.
The councils that confirmed it
The first lists matching today's 73-book Catholic Bible appear from local Church councils: Rome (382, under Pope Damasus I), Hippo (393), and Carthage (397) — the latter two under the influence of St. Augustine. These councils did not invent the canon; they formally recognized and closed a list that had already emerged through centuries of the Church's lived, worshipping practice, guided by the same teaching authority described on the Papacy & Magisterium page.
Trent and the Reformation
For over a thousand years afterward, this 73-book canon was simply the Bible of the Christian West. When the Protestant Reformers of the sixteenth century removed the Old Testament deuterocanonical books (calling them "Apocrypha") and set aside a few New Testament books as well, the Council of Trent responded in 1546 by solemnly and dogmatically defining the full 73-book canon — not creating something new, but formally closing the question in the face of a serious challenge, exactly as earlier councils had defined other doctrines under pressure.
Why Catholic Bibles have 73 books
Put simply: Catholic Bibles have 73 books (46 Old Testament, 27 New Testament) because that is the canon the Church — the same Church that, under the Spirit's guidance, recognized which Gospels were authentic — received, used, and formally confirmed centuries before the Reformation ever narrowed it to 66. This has a direct bearing on the question of Sola Scriptura ("Scripture alone"): see the related discussion on the Apologetics page for why the Bible's own table of contents already points back to the authority of the Church that assembled it.
A word of Scripture
"All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness." 2 Timothy 3:16