1 The literature of the Apocalypse is immense, but it is unequally distributed in regard both to time and to place of origin. From the Greek-speaking East, which produced the book, no exposition has reached us which is earlier than the sixth century, and none of any importance which is later than the tenth. The West, on the other hand, began to comment upon St John’s prophecy in the time of Diocletian, and has occupied itself with Apocalyptic problems from the days of Irenaeus to