Rev 17:10

17:10 five of whom have fallen. If Revelation was written about a.d. 67, these five may be the first five Roman emperors, beginning with Julius Caesar. The sixth is Nero, the currently reigning emperor. But it might also be the case that five simply represents an indefinite number of previous persecuting states (such as the beasts of Dan. 7). The presence of the sixth indicates in symbolic fashion that Christians are near the end, but not quite there.