The sentence as Eusebius quotes it here is incomplete; he repeats only so much of it as suits his purpose. Irenæus completes his sentence, after a few more dependent clauses, by saying, “I do not know how it is that some have erred, following the ordinary mode of speech, and have vitiated the middle number in the name,” &c. This shows that even in Irenæus’ time there was as much controversy about the interpretation of the Apocalypse as there has always been, and that at that day exegetes were as a rule in no better position than we are. Irenæus refers in this sentence to the fact that the Greek numerals were indicated by the letters of the alphabet: Alpha, “one,” Beta, “two,” &c.