There is controversy as to the dating of Revelation. There is evidence that suggests that John wrote Revelation in the early or middle 60s to prepare believers for the persecution under Nero and the coming of the Lord to execute judgment on Jerusalem, the great city where our Lord was crucified.
Wolfgang Schneider's work suggesting an early date on the subject can be cropped and summarized from his research as follows
The preface to the Aramaic Peshitta points to a time prior to 70 AD.
"The revelation which God gave the evanglist John on the island of Patmos where he had been banned by Nero Caesar."
The emperor Nero however died in 68 AD, and according to Roman rules those banned by a Cesaer would be released after the Caesar's death ... thus, John would have been released from Patmos in 68 AD (or shortly thereafter) and the time when he received this revelation and wrote it down would have been prior to 70 AD. John himself mentions in the book that he was at Patmos, when he received this revelation.
There are a number of points arising from the internal evidence, that is, from information given in the book itself, which all indicate the early date as not only probable but the only possible date for what is stated in the Book.
Warnings to seven churches in Asia
The Book of Revelation specifically mentions that this revelation was of special relevance to the seven churches in Asia and that John wrote it and had it sent to those churches by messengers (cp Rev 1:4). It is important to note that during Paul's ministry in the 50ies AD, there had been nine churches established in Asia. At about 60/61 AD there was a large earthquake in which, as we can read in secular sources, the cities of Colossae, Hierapolis and Laodicea were totally destroyed. Laodicea was the only city of these three which was rebuilt soon afterwards, which then left seven cities with churches in Asia. The period of time where there were only seven churches in Asia was only during the few years from the early 60ies AD to the time prior to the Jewish war.
An interesting detail from the message to the church at Philadelphia (cp Rev 3:7ff) also sheds some light on the possible time of writing. The believers at Philadelphia are warned by Christ in this revelation that an "hour of temptation" was imminent and "about to come upon all the world [the Roman empire]" and that they should hold fast and remain faithful... This is important and significant in that it is addressed to believers of a church in the 1st century AD and in that the first persecution of Christians all over the Roman empire took place under Nero Caesar in 64 AD. If this warning to the believers in Asia about an imminent temptation and the encouragement to hold fast related to this persecution, then the book seems to have been written even prior to 64 AD.
John's Post-Patmos Ministry
Another internal evidence in the book itself is connected to a reference about certain activities which John was still to experience in his life afterwards. In Rev 10:11, John is told that he "must prophesy again before many peoples, and nations, and tongues, and kings". Now, if John would have received this revelation in 96AD and written it at that time, then these words which he was told did not come to pass, seeing that he was a very old man at that time and hardly able to walk and travel. But, if John did receive this revelation and write it down during the time of Nero approx 65-66 AD, then he could fulfill what he was told. He would have been able to prophesy and to teach during the reigns of Caeasars Galba, Otho, Vitellius, Vespasian, Titus and also Domitian (spanning the time from 68-96 AD).
Destruction of city and temple at the end of the age
There are a number of references in the book of Revelation with symbols that have reference to the temple, and in addition Rev 11,1-2 makes reference to the destruction of the temple and the city of Jersualem. This event was also foretold by Jesus, when he prophesied about the judgment on Jerusalem which was to come by the Son of man at the end of the age.
There is a parallel record in Zec 14:2 about this "day of the Lord" with its destruction of Jerusalem and the temple, and Zec 13:7ff places this shortly after the shepherd would have dispersed his sheep (Jesus did quote from this section in Mt 26,31). Rev 11,2 is also a parallel to Mal 4, where a day of the Lord is spoken about when the Lord would separate and burn the chaff (the evil ones). This also parallels what Jesus mentions in parables about the burning of the chaff, the burning of apostate Israel, "at the end of the world [age]" (cp Mt 13:40,49).
Now, when is or was "the end of the system of things"? NT scriptures provide some insight as they mention certain things which happen in connection with the end of the age . The writer of Hebrews speaks of Jesus as "now once in the end of the world hath he appeared to put away sin by the sacrifice of himself." (Heb 9:26), (signalling the end of the law's hold) and we can see from this passage that "the end of the world [age]"is the time when the Messiah Jesus through his sacrifice put away sin; in other words, the "end of the age" was the time during which Jesus lived and fulfilled his ministry almost 2000 years ago.
The coming of Christ in Rev 1:7 is a mention of that coming when the Son of man would judge the enemies of his assembly and his coming to execute judgement on apostate Israel, it marks the events prophesied to happen at the end of the age.
From both external and internal evidence of the Book of Revelation, an early date is the only option which will harmonize well with the content of the book. Although the later date of 96 AD is widely accepted in many Christian circles and groups today (even though this theory basically only rests on one statement in one external source), the evidence in the book of Revelation itself points rather clearly to an earlier date of 65-66 AD for the time of writing, the time when John was banned to the Isle of Patmos during the persecution by Caeasar Nero.