Concerning the year and its parts.

The table above represents the "Table of Dominical letters from the Ides of October October 15 in the year of the correction 1582... until the year 1700 exclusive."

The use of this table is as follows: For the year of the correction, 1582, after the Ides of October (after ten days have first been removed), the letter c is assigned to the first cell. For the following year, 1583, the letter b is assigned to the second cell. For the year 1584, the letters A g are given to the third cell, and so on. Other cells are assigned to other years in order until the desired year is reached, returning to the beginning of the table as many times as you have run through it. The cell into which the proposed year falls, provided it is earlier than the year 1700, will give the Dominical Letter Also known as the Sunday Letter, used to determine which day of the week a date falls on of that year. If a single letter occurs, the year will be a common year; if it is double, it is a Leap Year Bissextilis: a year with an extra day. In that case, the upper letter shows the Sundays in the Calendar from the beginning of the year until the Feast of Saint Matthias the Apostle February 24, and the lower letter from this Feast until the end of the year.

For example: Suppose the Dominical Letter for the year 1587 is to be found. Count from the year 1582, which you assign to the first letter c, up to the year 1587, assigning a single year to each cell (counting any double letters, upper and lower, as one cell). The year 1587 falls on the letter d, which occupies the sixth place in the table. Therefore, for that entire year, the Dominical Letter is d, and it is a common year since only a single letter occurs. Again, suppose the Dominical Letter for the year 1616 is to be investigated. Count from the year 1582, as was said, up to the year 1616, returning to the beginning of the table after you have run through it. You will arrive at these two letters, c b, placed in the seventh spot. Therefore, that year is a Leap Year, since a double letter occurs. The upper letter c will indicate Sundays from the beginning of that year until the Feast of St. Matthias, and the lower letter b for the remainder of the year.

Another Table of Dominical letters from the year 1833 inclusive, until the year 1900 exclusive.

The use of this table is as follows. To the year 1833, the letter f is assigned in the first cell, and to the following year 1834, the letter e, and so on. Other cells are assigned to the remaining years in order until the desired year is reached, returning to the beginning of the table as many times as you have run through it. The cell into which the proposed year falls will give the Dominical Letter for that year. If a single one occurs, the year will be common; if double, it is a Leap Year. Then the upper letter will show Sundays in the Calendar from the beginning of the year until the Feast of St. Matthias the Apostle, and the lower one from this Feast until the end of the year.

Concerning the Indiction.

The Indiction A fifteen-year cycle used in ancient Rome and continued in legal and ecclesiastical documents for dating is a cycle of 15 years, from 1 to 15. When this cycle is finished, it returns again to one. Each year of this cycle begins in January for Papal Bulls. Since the use of Indictions is frequent in diplomas and public writings, we can easily find the current year of the Indiction for any given year from the following table, which is for perpetual use; however, it begins from the year of the correction, 1582.

Table of the Indiction from the year of the correction 1582.

If you assign the first number, which is 10, to the year 1582, and the second number, 11, to the following year 1583, and so on until the desired year, returning to the beginning of the table as many times as you run through it, the proposed year will fall on the Indiction being sought.

Concerning Movable Feasts.

By the decree of the holy Council of Nicaea, Easter Pascha, upon which the rest of the movable feasts depend, must be celebrated on the Sunday that immediately follows the 14th moon of the first month. Among the Hebrews, the first month is called that in which the 14th moon either falls on the day of the spring Equinox The time when day and night are of equal length, which happens on the 21st day of March, or follows it most closely. It follows that if the Epact The age of the moon on January 1st of any year is found, and from that Epact marked in the Calendar between March 8th inclusive and April 5th inclusive (for the 14th moon of this Epact falls either on the day of the spring Equinox, March 21st, or follows it most closely), fourteen days are counted inclusive downward. The next Sunday following this 14th day shall be Easter day. This is done so that we do not coincide with the Jews, should the 14th day of the moon happen to fall on a Sunday.

Example: In the year 1605, the Epact is 10, and the Dominical Letter is b. We find that Epact 10 is placed between March 8th and April 5th across from the day March 21st. If 14 days are counted downward from there, we find the 14th moon on April 3rd, which is a Sunday, since the Dominical Letter b is across from it. Therefore, so that we do not coincide with the Jews, who celebrate Passover on the 14th day of the moon, the Dominical Letter b must be taken which follows the 14th moon, namely the one placed across from April 10th. In that year, Easter must be celebrated on April 10th. Likewise, in the year 1604, the Epact is 29, and the double Dominical Letter is d c, since that year is a Leap Year. If 14 days are counted from Epact 29, which is placed across from April 1st (within the range of March 8th to April 5th), the 14th moon falls on April 14th. Because the second Dominical Letter, c, is then in effect, which is placed across from April 18th (after the 14th moon on April 14th), Easter will be celebrated that year on April 18th.

Furthermore, so that all movable feasts may be found more easily, the two following Paschal tables have been composed, one old and the other new. Movable feasts are found from the old one in this way: On the left side of the table...