INDICTION. In chronology, indiction is a full circle of fifteen Julian years. Know that the term first meant a tribute which the Romans collected every year in the provinces under the name of indictio tributaria . It is likely that this tribute was levied for the subsistence of soldiers, and particularly those who had served the republic for fifteen years. However that may be, when the state of the Roman empire changed its face under the last emperors, they kept the term indictio , but used it simply to measure an interval of fifteen years.

One would look in vain for the time when they began to use indiction in this last sense; we will never know. Those who say that Constantine, after abolishing the secular games and defeating Maxentius, introduced the epoch of indiction in the month of September 312, are no doubt guessing, since they cannot cite any proof.

The origin and beginning of the Roman, or if you wish pontifical, indiction has not been better identified; this second point of history is still one of the most obscure. Father Mabillon took fruitless pains to illuminate it, and Ducange was no more fortunate in his Glossary. [1]

What we know for sure is that the popes, after Charlemagne had made them sovereign, began to date their acts by the year of indiction , which was fixed at the first of January 313 A.D.; formerly they dated them by the years of the emperors, and finally they dated them by the years of their pontificate, as is proven by the synod that pope John XV held in 998. [2]

Today the Roman court, to prevent the falsities that could be committed in the provisions of benefices, in bulls and other missives, by changing their dates, has had the idea of multiplying them, adding others from small to large, and repeating the same date five or six times in various manners, which is an excellent precaution: for if the forger alters only some of the dates, he will be refuted by all the others; and if he alters all of them, it will be easy to discover his trickery by examining them closely.

The large dates of the chancellery are the current year of Our Lord and that of the reigning pope. The small dates are the current years of the indiction , of the golden number, [3] and of the solar cycle.

To understand the date of the current Roman indiction , you must remember that it was fixed at the first of January in the year 313 of the common era, whence it follows that the year 312 had an indiction of twelve, for dividing 312 by 15 has a remainder of 12; consequently, it was assumed that the cycle of the indiction would begin 3 years before the birth of Christ, a fictional calculation that has no relation to celestial movements.

So now if you want to know the number of the Roman indiction that corresponds to a given year, add 3 to the given year and divide the sum by 15: the remainder after the division, without regard for the quotient, is the desired number of indiction .

If you were asked, for example, the number of the papal indiction that corresponds to the year 1700, you will add 3 to 700 and divide the sum of 1703 by 15: the remainder of the division will yield 8, which is the indiction number for the year 1700.

Likewise, to find the indiction of the year 1759, you will add 3 to 1759, which will make 1762, and divide 1762 by 15: the remainder will be 7 for the desired indiction number; same operation with respect to any other year.

The indiction at its origin did not designate, as we have already said, a chronological epoch. This word comes from the Latin indictio , which means declaration , ordinance . The indiction time of the Roman emperors was the time when the people were summoned to pay a certain tribute, and this imperial indiction took place towards the end of September or the beginning of October because then, the harvest being over, the people could pay the tribute ordered, tributum indictum .

1. Jean Mabillon (1632–1707), Benedictine historian who published many histories and a Méthode pour apprendre l'histoire (1684); Charles du Fresne, sieur Ducange (1610–1688), Glossarium ad scriptores mediae et infimae latinitatis (‘Glossary of writers in medieval and late Latin’), 1678. The link is to a 1681 edition published in Frankfurt.

2. A typo in the original says 1998.

3. Nombre d’or : a chronological device unrelated to the golden ratio, also called nombre d’or : see the article Nombre d’or in the Encyclopédie .