Did Catholics Add to the Bible at Trent?

A Closer Look at the Council of Trent, the Biblical Canon, and the Books You May Not Know Were Always There

How many books are there in the Bible? This was a question I was asked at a recent Catenian quiz. I confidently answered: 73 of course. But I got no points for my answers which was marked incorrect. Why? Because the Catholic Quiz Master had relied on Google to get answers to his questions and Google had answered 66. Why the discrepancy?

It’s a common claim in Protestant circles — often confidently stated, sometimes sarcastically tweeted — that the Catholic Church “added” seven extra books to the Bible at the Council of Trent in the 16th century. A recent X post (linked here) typifies the tone:

"The Deuterocanonicals are apocryphal. Catholics added them at Trent to shore up doctrines they couldn't find in the Bible."

This assertion has become a kind of shorthand amongst Protestants for discrediting Catholicism as a corruptor of Scripture, or as an institution scrambling to invent doctrines like Purgatory or prayers for the dead by smuggling in “non-biblical” books centuries after the biblical canon was supposedly closed.

But is this really what happened?

Let’s take a moment to look at what actually happened. History — especially Church history — is rarely that tidy. Often, it’s messier, more fascinating, and more nuanced than the slogans allow. If you're willing to go deeper, you may find that the canon of Scripture, far from being a clean-cut list from the beginning, developed in a living Church deeply rooted in both Jewish tradition and the authority given by Christ to His Apostles and their successors.

So, did Catholics "add" the Deuterocanon at Trent?

The Historical Backdrop

First, what are we talking about? The Deuterocanonical books (from the Greek deutero, meaning "second") refer to seven Old Testament books (Tobit, Judith, Wisdom, Sirach, Baruch, and 1 and 2 Maccabees, plus additions to Daniel and Esther) that are included in Catholic and Orthodox Bibles but are not found in most Protestant editions.

The common Protestant version of the Old Testament follows the Hebrew Masoretic Text, which was formalised by Jewish rabbis between the 7th and 10th centuries AD but draws on earlier Pharisaic traditions that narrowed the scope of accepted Scriptures, traditions that arose in part in opposition to the growing Christian movement, an important fact which is often overlooked by advocates of the shorter canon.

Catholics, by contrast, base their Old Testament primarily on the Septuagint, a Greek translation of the Hebrew Scriptures produced by Jewish scholars in Alexandria beginning in the 3rd century BC. The Septuagint was the Bible of the early Church. It was the version most often quoted by the apostles and the one used in most early Christian worship.

In fact, when Paul writes in 2 Timothy 3:16 that “all Scripture is inspired by God”, the only complete Scripture in widespread use was the Septuagint — and that includes the Deuterocanonical books.

Before Trent: The Canon Was Already Known

Contrary to popular assumption, the Deuterocanonical books were not “added” by the Catholic Church at the Council of Trent (1546). They had been in widespread use in Christian communities for well over a millennium by then.

Here are the facts:

• 382 AD: The Synod of Rome, under Pope Damasus I, issued a list of canonical books — including the Deuterocanon — matching the modern Catholic Bible.

• 393, 397, and 419 AD: The Councils of Hippo and Carthage, which included St. Augustine, also confirmed this list.

• 405 AD: Pope Innocent I affirmed the canon in a letter to the Bishop of Toulouse.

• 787 AD: The Second Council of Nicaea, an ecumenical council, accepted the canonicity of the Deuterocanon.

• 13th century: The Latin Vulgate, translated by St. Jerome (who had his doubts, but translated the Deuterocanon anyway), was used universally in the Church — and included all 73 books.

That’s over 1,100 years of consistent usage before the Reformation.

When the Reformers emerged in the 16th century, Martin Luther removed the Deuterocanonical books from the Old Testament canon. His justification? They weren’t part of the Jewish canon, a position shaped largely by post-Christian rabbinical decisions at Jamnia (~90 AD), a council convened in the wake of the destruction of the Temple.

But should Christians determine their canon based on a post-Christian rabbinical council?

Rabbinic Judaism distanced itself from the Deuterocanonical books precisely because Christians were using them to proclaim Jesus as the Messiah. Books like Wisdom of Solomon and 2 Maccabees contain ideas closely aligned with Christian theology (e.g., resurrection, messianic expectation, prayers for the dead). This suggests that these texts were spiritually potent — and their rejection was at least partly anti-Christian in motivation.

The exclusion of the Deuterocanonical books from the Protestant Bible represents a significant break from the scriptural tradition of the early Church. These books were part of the Septuagint, the Old Testament used by Jesus, the Apostles, and the earliest Christians, and were cherished in Christian liturgy and theology for over a thousand years. When Rabbinic Judaism began distancing itself from these texts after 70 AD, it did so in part because early Christians were using them to proclaim Jesus as the Messiah. Later, during the Reformation, Protestant leaders rejected the Deuterocanon not because of ancient Christian authority, but because these books supported doctrines they opposed, such as purgatory and prayers for the dead. What emerged was a 66-book canon shaped more by post-Christian Jewish decisions and 16th-century theological disputes than by apostolic tradition. To restore the Deuterocanon is not to add to Scripture — it is to reclaim a fuller, more authentic biblical inheritance rooted in the earliest Christian faith. In short, this historical context strongly supports the argument that the Deuterocanonical books rightly belong in the Christian biblical canon — and that their exclusion in the 66-book Protestant canon reflects a later, narrower reinterpretation of the faith that diverged from the beliefs and practices of the early Church.

It was in response to this growing rejection that the Council of Trent acted. The Deuterocanon wasn’t added — it was reaffirmed. Declared dogmatically. Bound definitively. But the content had been there all along.

The New Testament and the Deuterocanon