I will assume an early date from the inspired evidence of the text itself.
The late date is normally inferred from a quote from the writings of Irenaeus -
http://www.cmfnow.com/articles/pb057.htm - but that is ambiguous.
The relevance of the date is the key to understanding the prophecy.
In the Amillennial understanding of
Revelation, it matters not at all whether the book was written before or after AD 70. However, it seems to be that a post-AD 70 date is the most likely, for the following reasons:
1. The earliest writers are unanimous that the Apostle John lived to a great age, and therefore a later date is possible.
2. Although Irenaeus is unclear, Eusebius (
Eccl. Hist. 3.18.1 and 3.20.8-9) quotes an early writer called Hegesippus who seems to say that John was banished to Patmos by the Emperor Domitian and freed to go to Ephesus by Nerva.
3. A literal rather than symbolic interpretation of the 1,260 days/42 months to prove an early date causes problems. There are places where a literal interpretation seems to fail (12:6; 13:5). Next, the other dates don't fit. The Jewish revolt broke out in Spring AD 66, and the destruction of Jerusalem occurred in Aug-Sept of 70. The trampling of the city could only begin when the Roman soldiers occupied it in 70; what happened 3 and a half years later?
4. To point to Nero as the fulfilment of the number 666 leads to all sorts of problems. Details on request.
5. Preterists point to the measuring of the Temple in 11:1-3 as evidence that the Temple must still have been standing. The N.T. uses the Greek word
hieron for the Temple complex (eg. Matthew 24:1; Acts 3:1) and
naos for the inner sanctuary (eg. Matthew 27:51). John only uses
naos (16 times!). Christians are now the Temple of God (
naos. 1 Corinthians 6:19; 2 Corinthians 6:16) and we, in Christ, enter into the
naos, the holiest place (Hebrews 9:24; 10:19ff).
Is it largely fulfilled by the AD 70 destruction, with (amillennial) application to the church down the ages?
or
Is it yet future with rapture/tribulation/millennial fulfilment?
or
Is it specifically being fulfilled down the ages, with respect to to rise of Catholicism, Islam, the Reformation, the black death, world wars, etc?
Some of the Olivet Discourse was obviously fulfilled by the destruction of Jerusalem, though other parts were not. I do not believe that Revelation has any connection to AD 70. This, in fact, is one of the main reasons why I am Amil. I reject the Dispensationalist interpretation because what help would it have been to struggling Christians in the 1st Century to know that this or that was going to happen thousands of years later? Likewise, what help is it to us today if almost all prophecy was fulfilled 2,000 years ago? I do not believe that
Revelation speaks directly of the Church of Rome, Black Death or Islam, though it certainly speaks of false religion, State religion, anti-Christian government, persecution, the 'world' ( in the 1 John 2:15 sense of the word) and the judgements of God upon the wickedness of Man. These are things that were going on at the time the book was written and will continue until our Lord returns.