As far as I know ... Revelations was written by an early Jewish convert to Christianity, shortly after the Romans destroyed Jerusalem. And the book is an anti-Roman propaganda piece.
The number 666 is Nero's imperial name, spelled out in Jewish numerology.
In fact, the decision to even include Revelations in the Bible is largely due to Bishop Athanasius, a pugnacious church leader who championed Revelation about 360 years after the death of Jesus. Athanasius was so fiery that during his 46 years as bishop he was deposed and exiled five times. He was primarily responsible for shaping the New Testament while excluding books he labeled as hearsay. Many church leaders opposed including Revelation in the New Testament. Athanasius’s predecessor said the book was “unintelligible, irrational and false.”
Athanasius, though, saw Revelation as a useful political tool. He transformed it into an attack ad against Christians who questioned him. Rome was no longer the enemy; those who questioned church authority were the anti-Christs in Athanasius’s reading of Revelation.