Some may find it interesting that Revelation took some time before it was accepted in the canon of the New Testament. The western church (western Europe) did seem to accept the book from the beginning, but the eastern church (eastern Europe, western Asia, northeastern Africa) didn’t take to it as well. Most of the doubts centered on the authorship of the letter. Dionysius, an early bishop of Alexandria from 248 to 264 A.D., thought the differences between the Gospel of John and the Apocalypse were enough to pronounce the Apocalypse as not being written by John. This influenced others to not accept the book in the east. As a result of all of the this, the book didn’t make the list of canonical books at the Council of Laodicea in 360 A.D. In 397, it got added to the canonical list at the Council of Carthage mostly due to a single person, Athanasius, who fully accepted it.. Finally, Revelation was accepted and canonized in 680 at the Council of Constantinople. Osborne*** (Pgs. 23-24).
As one can see, the Apocalypse went through a many centuries before it became a book of the New Testament. As one might expect, there were other books of the New Testament that faced similar treatment.
As a side note to this, most people don’t know that it took centuries before the canon of the New Testament was set. As we can see here, it took around 500 years to set the entire New Testament to what we see today as the New Testament.
***Revelation (Baker Exegetical Commentary on the New Testament) Grant R. Osborne