But this again is held by other wise and most acute men to be an impossibility, because within that narrow and most contracted limit of a cycle of nineteen years, a thoroughly genuine Paschal time, that is to say, one held on the Lord's day and yet after the equinox, cannot occur. But, in order that we may set in a clearer light the difficulty which causes their incredulity, we shall set down, along with the courses of the moon, that cycle of years which we have mentioned; the days being computed before in which the year rolls on in its alternating courses, by Kalends and Ides and Nones, and by the sun's ascent and descent.