I suspect that on some Tuesday afternoon in AD 41 the apostle Mark was hanging out with the guys in the olive grove near Peter’s place. They were in a bit of a quandary: Their once exciting role recounting the stories of Jesus was, well to be blunt… becoming a bit of a pain as lots converts were coming up saying “So and so said that Jesus…”.
They each remembered Jesus’s actions and words though of course they all differed on details, some being personal and some public. Clearly it was time to get the record straight so by consensus (which meant that the others thought Mark had the least to do) he took on the role of writing down what he remembered.
Mark also wanted to get in with another other local group so to cover their story he added quite a bit about their deceased teacher John the Baptist. In fact there was quite a bit of competition between the two groups each with their own deceased leader and claims of offering salvation for Israel.
At the time all writing was done on parchment and then patiently copied by hand so the text was slow to spread, but spread it did. Mark’s version became the base story and only after that did John go to Patmos, have his visions and then write them down in The Book of Revelation.
When exactly this was done is disputed, I prefer an early date (perhaps as early as 65 AD) but many scholars put the writing of the book later perhaps about 84 AD. Either way about 70 AD the Romans decided on urban re-development in Jerusalem so as to make a statement that they were in charge.
With their temple destroyed the Jewish religion changed into a decentralized Rabbinic diaspora, with a scattered network of Synagogues. This change was reflected also in the Christian sect (which the Romans sensibly regarded as part of that ‘Jewish lot’) and with the scattering and without a central core the dispersed groups evolved differences over time.
Then two more synoptic gospels were written. ‘Synoptic’ roughly means ‘telling the same basic story’ so Mark’s gospel was used by Matthew and Luke as the base for their books.
NB: Should you have ever read the New Testament you may have noticed that Luke isn’t actually listed in the cast. His body of work also included the ‘Act of the Apostles’ so he’s really into fixing in place a narrative about the creation of the Christian movement.
These synoptic Gospels include details alluding to the destruction of the Jerusalem temple (prophecies etc added in after the event) which is how we can date them. The Book of Revelation doesn’t have such intimations which again is why I feel it probably was written before the destruction of the temple.
This fussing about with ‘what books’ isn’t just Biblical History – it implies that these books were written with an agenda. They weren’t just “The Adventures of Jesus Christ and his Disciples” – people were deliberately included, excluded, highlighted or even re-assigned to bit roles, depending on the author and editors viewpoint.
Of importance to us is that late in the first century, St John read all these various Gospels in circulation and was struck with the realization that “You’re a silly bunch of Galileans! You’ve missed the really important bit..”
St John’s version of a Gospel had a lot less of the historic details and more of the important bits. In our terms it meant he wrote metaphorical, even mythological tales, pointing out ‘truths’ that needed to be realized if a person was to be like Christ.
John wrote Revelation first, at an an early time when ‘editing’ to fit approved doctrine was still in the future. His Gospel was written later than the other gospels with some letters perhaps in between. By that time Jesus’s brother James was dead, St Peter crucified and Paul headed for the chop in Rome.
St. John’s authority in the Church as a ‘chosen by Jesus’ apostle and keeper of Mary the mother would have been immense. This perhaps more than any reason is why The Book of the Revelation to St John is still canon. Through twenty centuries it has been a source of discomfort to many, yet it has been preserved.
It may be the fact that a good ‘old fashioned’ curse on anyone who tampered with the work was included in it kept many ‘Bible Editorial Committee’ from dropping the book from the Canon. People back then had a sensible fear of smoting.