I.

As we are about to speak on the subject of the order of the times and alternations of the world, we shall first dispose of the positions of diverse calculators; who, by reckoning only by the course of the moon, and leaving out of account the ascent and descent of the sun, with the addition of certain problems, have constructed diverse periods, ^[1156] self-contradictory, and such as are never found in the reckoning of a true computation; since it is certain that no mode of computation is to be approved, in which these two measures are not found together. For even in the ancient exemplars, that is, in the books of the Hebrews and Greeks, we find not only the course of the moon, but also that of the sun, and, indeed, not simply its course in the general, ^[1157] but even the separate and minutest moments of its hours all calculated, as we shall show at the proper time, when the matter in hand demands it. Of these Hippolytus made up a period of sixteen years with certain unknown courses of the moon. Others have reckoned by a period of twenty-five years, others by thirty, and some by eighty-four years, without, however, teaching thereby an exact method of calculating Easter. But our predecessors, men most learned in the books of the Hebrews and Greeks,—I mean Isidore and Jerome and Clement,—although they have noted similar beginnings for the months just as they differ also in language, have, nevertheless, come harmoniously to one and the same most exact reckoning of Easter, day and month and season meeting in accord with the highest honour for the Lord's resurrection. ^[1158] But Origen also, the most erudite of all, and the acutest in making calculations,—a man, too, to whom the epithet chalkeutes ^[1159] is given,—has published in a very elegant manner a little book on Easter. And in this book, while declaring, with respect to the day of Easter, that attention must be given not only to the course of the moon and the transit of the equinox, but also to the passage (transcensum) of the sun, which removes every foul ambush and offence of all darkness, and brings on the advent of light and the power and inspiration of the elements of the whole world, he speaks thus: In the (matter of the) day of Easter, he remarks, I do not say that it is to be observed that the Lord's day should be found, and the seven ^[1160] days of the moon which are to elapse, but that the sun should pass that division, to wit, between light and darkness, constituted in an equality by the dispensation of the Lord at the beginning of the world; and that, from one hour to two hours, from two to three, from three to four, from four to five, from five to six hours, while the light is increasing in the ascent of the sun, the darkness should decrease. ^[1161] ...and the addition of the twentieth number being completed, twelve parts should be supplied in one and the same day. But if I should have attempted to add any little drop of mine ^[1162] after the exuberant streams of the eloquence and science of some, what else should there be to believe but that it should be ascribed by all to ostentation, and, to speak more truly, to madness, did not the assistance of your promised prayers animate us for a little? For we believe that nothing is impossible to your power of prayer, and to your faith. Strengthened, therefore, by this confidence, we shall set bashfulness aside, and shall enter this most deep and unforeseen sea of the obscurest calculation, in which swelling questions and problems surge around us on all sides.