in March or in April the Pascha falls, know that there are as many days dedicated to the fast of the holy apostles.
OF THE MOST BLESSED ANDREW OF CRETE, OF JERUSALEM
A METHOD FOR FINDING THE CYCLE OF THE SUN, WORKED OUT CAREFULLY FOR THE SAKE OF THOSE FOND OF LEARNING.
B Take the years beneath the thousands and hundreds from the creation of the world, and add another twenty-four; and make a sum; and subtract them by twenty-eight; and what remains in your hand is the cycle of the sun. And do thus every year.
Likewise also concerning the moon. Take the same remainders of the thousands and hundreds from the creation of the world; add another seventeen; and make them a sum; and subtract by nineteen; and what remains in your hand is the cycle of the moon.
Likewise also the indiction is raised, that is, year by year. Take the years from the creation of the world; add them all, C and subtract them by fifteen; and what remains in your hand is the indiction.
Know also this, that the sun begins from the first of the month of October; but the moon from the first of the month of January; and the indiction from the first of the month of September.
To find the legal Pascha, take the cycle of the moon of the year in question, and multiply it by eleven; add to it also another six "from time immemorial"; but it must be known that in the seventeenth cycle, and the eighteenth, and the nineteenth, you do not add the six "from time immemorial," but seven; but in all the other cycles, six only, as we have said. Then thus divide them by thirty; and keep those below thirty; starting from the month of March, count above them, until you complete fifty days; and if the fifty days are completed within the month of March, thanks be to God; but if not, take also from the month of April, until you complete them. On whatever day the fifty days are completed, on that same day, in the year in question, falls the legal Pascha.
A
How the weekday of the legal Pascha is to be sought.
Take the solar cycle, and the bissextile days of the years that have elapsed. Add the days of the month on which the legal Pascha falls, up to the Pascha itself. If the legal Pascha should fall in the month of March, add eleven to the sum, on account of the four months, from October, that is, to January: in such a way that for the month which has thirty days, you take two; for that which consists of thirty-one, three. But if the legal Pascha falls in the month of April, add three on account of March. Fourteen will be gathered. When all these have been reduced to a single sum, divide it by seven; the remainder will give the weekday of the legal Pascha. Once this is found, advance to the Sunday, just as you have learned. Thus you will find the Christian Pascha.
Method of finding the Christian Pascha.
Take the cycle of the sun for the proposed year: to this add the past bissextile years; in such a way that you take one day for every four years. Then, if the legal Pascha falls in the month of March, add its epacts, which are five. But if it falls in April, add one, its epact. When you have combined everything, divide by seven; and that which is below the seven indicates the initial day of the month in which the legal Pascha occurs. Then, having done this, count from that initial day, so that you may find on which day the legal Pascha falls. Once you have found it, if it is a Sunday, advance to the following Sunday; there the Christian Pascha will fall. If it is a Monday, [do] likewise to the coming Sunday, and so on up to the Saturday; for both Paschas occur in the same week, but by no means on the same day. B
But it must be known how the monthly epacts are formed. The year consists of 365 days. These, divided by seven, leave one day remaining. Therefore, add this one, and also three from October, and they become four. Add these to November. Keep the four again, and add two from November; they become six, the epacts of December. To these, let three be added from December, and from the sum of nine, remove seven; two remain, the epacts of January. Add three for January, and there will be five as the epacts of February, which also C correspond to March. Now to these five of March, add three. Eight are gathered, from which, if seven are subtracted, one remains, the epact of April. For April, add two; they will become three, the epacts of May: which, with three added, makes the epacts of June six. Two days are added for June, and from the sum of eight, with seven removed, one remains, the epact of July. Then, with three added for July, the epacts of August become four. August adds three, and in that way seven epacts of September arise. In this manner the propagation of the epacts is explained; which is thus proposed in summary. D