Revelation is believed to have been written around 90 AD by John, the last surviving Apostle.
No, actually, the current thinking on the subject is that John of Patmos was not the same John of the Gospels. There are lots of reasons for this, primarily in style and how Revelation is put together, in comparison with John’s Gospel. Kinda like the difference in writing styles between Tom Clancy and Steven King.
So?