I don't entirely know where this belief comes from, but it's a myth, or at least a considerably problematic misunderstanding, to think that there was 'a Christian bible' and then that 'books were removed from it'.

When Christians first appear, in the middle of the 1st century, the utilise the Jewish scriptures or Hebrew bible as their own. They also write a body of new literature, which is circulated, and pretty quickly gains recognition as authoritative. This is seen partly by its wide distribution, partly by the way 2nd century authors treat 1st century texts as authoritative and indeed inspired. A fair core of this is consistently used and treated so, and that core goes on to become the New Testament.

But it's a core that's a bit hazy around the edges. This is complicated by the fact that no one at HQ (not that there really is a HQ) is sitting down giving out stamps of approval. Different communities have different collections of texts, and in some places one book might be in, another might be out.

Of the canonical NT, the smaller letters (Jude, 2, 3, John, 2 Peter) and Revelation tend to be under the most suspicion, while the best contender that didn't make it in is probably Shepherd of Hermas.

So the 2nd century sees both a shift in the kind of Christian writing produced, a change in how the 1st century documents are treated, and a proliferation of new 'gospels' and other texts. Many of the other gospels and acts books appear to have 2nd century dates and although often popular, did not receive wide approval.

Throughout this period you also have the regula fidei, or Rule of Faith, operating, which is a sense of the common belief of the church, handed down through time, and universal through all communities. This functions as a form of tradition to safeguard the universalistic concept of the churches against idiosyncratic heresies.

It's not really until the 3rd and even more so the 4th century that you start to see settled "lists" of books in the New Testament emerging. Partly I think this is the result of the rise of Councils themselves, partly a process of growing self-reflection around the idea of canonical books.

But at no stage would you really say 'books were removed', any more than saying 'books were added', because there was not really a group that acted with authority to do so to a pre-existing "set" of books.

I wonder if you're thinking about the Apocrypha? Catholic and Orthodox bibles often (not always) include 6 other books (for Catholics, the Orthodox number is slightly different), such as Macabees 1 and 2, which are viewed as less reliable than the OT and NT texts (hence the title Apocrypha). Protestant Bibles omit them.