The history of Revelation’s path into the biblical canon is unusual. Other debated books of the Bible began with a mixed reception and gained more and more acceptance over time. Revelation’s experience was nearly the opposite, going from accepted to disputed back to accepted again over several centuries.
It was accepted throughout the church in the first century after it was written, being used and approved by Hermas, Melito, Justin Martyr, Irenaeus (his position is questioned by some), Clement of Alexandria, Origen, Hyppolytus and Tertullian. It was also included in the earliest list of authoritative New Testament books, the Muratorian Canon.
But in the Third Century, when the visionary Montanists in the east used Revelation to legitimate their own prophetic claims, their opponents responded by casting doubt on the legitimacy of the book. These doubts led to Revelation’s place in the canon being questioned in the Third and Fourth Centuries, especially in the eastern part of the Empire. As a result, Revelation was accepted into the canon fairly quickly in the Western Church, but was not fully accepted in the East until the Fifth and Sixth Centuries. In the end, its broad early support among the Church Fathers, combined with its role as a compelling capstone to the Bible, led to its full acceptance as Scripture.