CYCLE OF INDICTION, AND THE JULIAN PERIOD.
The cycle of Indiction or Roman Indiction, is a period of fifteen years;
not astronomical like the two former, but entirely arbitrary. Its origin
and the purpose for which it was established are alike uncertain; but it
is conjectured that it was introduced by Constantine the Great, about the
year 312 of the common era, and had reference to certain judicial acts
that took place under the Greek emperors at stated intervals of fifteen
years. In chronological reckoning, it is considered as having commenced on
the first day of January of the year 313.
By extending it backward, it will be found that the cycle commenced three
years before the beginning of our era. In order, therefore, to find the
number of any year in the cycle of indiction, we have this rule: Add three
to the date, divide the number by fifteen; and the remainder is the year
of the indiction. Should there be no remainder, the proposed year is the
fifteenth or last of the cycle. Thus, for the year 1892, we have (1892 +
3) / 15 = 126, remainder 5. Therefore, 5 is the number in the cycle.
The Julian period, proposed by the celebrated Joseph Scaliger, as an
universal measure of chronology, is a period of 7980 years, and is formed
by the continual multiplication of the three numbers, 28, 19 and 15; that
is, of the cycle of the sun, the cycle of the moon, and the cycle of
indiction. Thus, (28 x 19 x 15) = 7980. In the course of this long period
no two years can be expressed by the same numbers in all the three cycles.
The first year of the Christian era had 10 for its number in the cycle of
the sun, 2 in the cycle of the moon, and 4 in the cycle of the indiction.
Now, it is found by actual calculation, that the only number less than
7980 which, on being divided successively by 28, 19, and 15, leaves the
respective remainders 10, 2 and 4, is 4714. Hence, the first year of the
Christian era corresponded with the year 4714 of the Julian period, which
period coincides with the 710th before the common mundane era 4004 B. C.;
for 4004 + 710 = 4714. Hence, also, the year of our era corresponding to
any other year of the period, or _vice versa_, is found by the following
rule:
When the given year is anterior to the commencement of the era, subtract
the number of the year of the Julian period from 4714, and the remainder
is the year before Christ; or, subtract the year before Christ from 4714,
and the remainder is the corresponding year in the Julian period. Thus,
Rome was founded in the year 3960 of the Julian period. What was the year
before Christ? We have then 4714 - 3960 = 754. Julius Caesar was
assassinated 44 years before Christ, what was the corresponding year of
the Julian period? We have then, 4714 - 44 = 4670.
When the given year is after Christ, subtract 4713 from the year of the
period, and the remainder is the year of the era; or add 4713 to the year
of the era, and the sum is the corresponding year in the Julian period.
Thus, the Council of Nice was convened in the year 5038 of the Julian
period, what was the year of our era? We have then, 5038 - 4713 = 325.
What year of the Julian period corresponds with the present year, 1892? We
have then, 4713 + 1892 = 6605.