In the Church a tradition arose that, in spite of all this, there was no direct connection between the events of 68-70 and the composition of the Apocalypse; and this tradition gains importance from the fact that it most probably originated in the Ephesian Church which was especially devoted to the memory of St. John. The Apocalypse was thought to allude to the last years of the apostle, in the time of Domitian; probably because it was interpreted as the apostle's answer to that Emperor's decrees, which inaugurated a grim period of persecution for the Church. The fate of Jerusalem and the devotion of the apostles to her--sealed with their life's blood--was soon forgotten by later generations, and even became entirely unintelligible and unknown. There is, however, probably not only a logical but a chronological connection between the Apocalypse and the events of 68 and 69. It is not likely that the seer saw himself measuring the Temple long after its destruction, nor would he have made the witnesses come to Jerusalem at a time when the city was almost in ruins and the capital transferred to Jabneh. Nor again would he have described the succession of Emperors as he does if he had written the Apocalypse many years after Nero's death. For the sixth head, who was reigning at the time he wrote, is followed by the seventh and last, who is made to reign only a short time before he is succeeded by Antichrist. It is of course impossible to date the Apocalypse with precision, for it is not quite clear which of the generals who usurped the emperorship, Galba or Vespasian, is identified with the sixth head. But this does not alter the fact that the prophecy reflects the events of 68 and 69.
from page 287, The Church of the New Testament Period